Develop Reference

Custom passwordToggleDrawable is too large in TextInputLayout

I have used android.support.design.widget.TextInputLayout to make a password input that allows the user to toggle readability on the password. The xml is as follows:
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:hintEnabled="false"
app:passwordToggleDrawable="#drawable/password_toggle_selector"
app:passwordToggleEnabled="true" >
<android.support.design.widget.TextInputEditText
android:id="#+id/password"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:hint="Password"
android:inputType="textPassword"/>
</android.support.design.widget.TextInputLayout>
The drawable selector is as described by How to customize android passwordToggleDrawable
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#drawable/password_toggle_show"
android:state_checked="true"/>
<item android:drawable="#drawable/password_toggle_hide"/>
</selector>
The issue is that the custom drawable becomes really large. Not larger than the edittext, but rather it seems to maximize its size while still fitting inside it (so, it seems to be bounded by the height of the element). However, if I leave the passwordToggleDrawable property unset, the drawable for the toggle is sized as is normal for android (I am sure you have seen the icon in other apps before). After much searching I have found a way to resize the custom one, but I am not happy with how its done (requires 2 extra xml files per drawable) and it only works for API 23+.
I would like to know if there is a good way to set the size of the drawable, or better yet, make it target the size of the default drawable?
I have tried setting the padding of the EditText as the source of TextInputLayout says that it gets the four paddings from it and apply to the mPasswordToggleView (line 1143), but it made no change on the icon and (as expected) also affected the padding of the EditText. I have tried setting minheight to 0. I have also tried changing between EditText and TextInputEditText (using the latter now as it seems to be recommended). I have tried switching the layout_height properties to wrap_content. I have tried scaling the drawable using xml's <scale> tag with the scale properties set. I have tried similarly with the <inset> tag. But none of those methods works.
The way I found (and am currently using) to resize the drawable that actually works is by using the xml tag <layer-list>, while setting the width and height properties. Then the <selector> xml file references those resized drawables instead of the png ones. But I don't like this solution because as I mentioned it requires API 23 and because of that results in a total of 4 extra xml files. It also sets the width and height by themselves, instead of keeping the ratio locked.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:drawable="#drawable/password_toggle_hide"
android:width="22dp"
android:height="15dp"/>
</layer-list>
TL;DR
How do I set the size of a custom passwordToggleDrawable in TextInputLayout? Preferably to same size as the default drawable.

I know this is an old question, but I faced the same problem and I believe I figure out a simple solution for this.
I'm using the TextInputLayout for the newest material library, and the only thing that I did was to find the reference for the endIcon from the TextInputLayout and change it's minimum dimensions.
val dimension = //here you get the dimension you want to
val endIconImageView = yourTextInputLayout.findViewById<ImageView>(R.id.text_input_end_icon)
endIconImageView.minimumHeight = dimension
endIconImageView.minimumWidth = dimension
yourTextInputLayout.requestLayout()
Important things to notice:
I did this on the OnFinishedInflated from a custom TextInputLayout, but I believe it will work fine on some activity class.
Cheers!

I face same problem. To avoid this situation I used png and set them based dpi like drawable-hdpi, drawable-mdpi etc. Also make those drawable as per radio. Hope that this tricks also work for you.

I were unable to find any solution to the question I actually asked, but I decided to instead solve the issue by disregarding the "in InputTextLayout" part of the question and implemented my own version of the class.
Mostly it is just a copy of InputTextLayout (sadly that class doesnt translate well for subclassing as everything is private) but with most of the stuff I dont need removed, and more importantly, with the CheckableImageButton mPasswordToggleView changed to a ViewGroup containing a View.
The ViewGroup is the clickable button, and handles setMinimumDimensions to keep the clickable area at min 48 dp, like the original did through design_text_input_password_icon.xml. This also makes small drawables not hug the right side of the screen as they are centered in the clickable area, giving the margin that the default drawable appears to have.
The View (or more precisely, a new subclass of it I called CheckableView) is the actual drawable (setBackground()), replacing the CheckableImageButton as the container of the drawable that lets it switch based on state_checked selector.
The xml-property passwordToggleSize allows a dimension to be set, which is used to scale the drawable. I opted to only have one value instead of width&height, and the drawable scales with its ratio locked such that its greatest dimension matches the dimension specified. I made the default size 24dp, as is specified for the default-drawable in design_ic_visibility.xml.
PasswordToggleLayout.java:
import android.content.Context;
import android.content.res.ColorStateList;
import android.content.res.TypedArray;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.annotation.Nullable;
import android.support.v4.graphics.drawable.DrawableCompat;
import android.support.v4.view.AbsSavedState;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.TextViewCompat;
import android.text.method.PasswordTransformationMethod;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import com.mylifediary.android.client.R;
public class PasswordToggleLayout extends LinearLayout {
// Default values from InputTextLayout's drawable and inflated layout
final int BUTTON_MIN_SIZE = 48; // The button is 48 dp at minimum.
final int DEFAULT_DRAWABLE_SIZE = 24; // The default drawable is 24 dp.
int mButtonMinSize;
final FrameLayout mInputFrame;
EditText mEditText;
private boolean mPasswordToggleEnabled;
private Drawable mPasswordToggleDrawable;
private CharSequence mPasswordToggleContentDesc;
ViewGroup mPasswordToggleViewGroup;
CheckableView mPasswordToggleView;
private boolean mPasswordToggledVisible;
private int mPasswordToggleSize;
private Drawable mPasswordToggleDummyDrawable;
private Drawable mOriginalEditTextEndDrawable;
private ColorStateList mPasswordToggleTintList;
private boolean mHasPasswordToggleTintList;
public PasswordToggleLayout(Context context) {
this(context, null);
}
public PasswordToggleLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public PasswordToggleLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
setOrientation(VERTICAL);
setWillNotDraw(false);
setAddStatesFromChildren(true);
mButtonMinSize = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, BUTTON_MIN_SIZE,
getResources().getDisplayMetrics());
mInputFrame = new FrameLayout(context);
mInputFrame.setAddStatesFromChildren(true);
addView(mInputFrame);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.PasswordToggleLayout, defStyleAttr,
R.style.Widget_Design_TextInputLayout);
mPasswordToggleEnabled = a.getBoolean(
R.styleable.PasswordToggleLayout_passwordToggleEnabled, false);
mPasswordToggleDrawable = a.getDrawable(
R.styleable.PasswordToggleLayout_passwordToggleDrawable);
mPasswordToggleContentDesc = a.getText(
R.styleable.PasswordToggleLayout_passwordToggleContentDescription);
if (a.hasValue(R.styleable.PasswordToggleLayout_passwordToggleTint)) {
mHasPasswordToggleTintList = true;
mPasswordToggleTintList = a.getColorStateList(
R.styleable.PasswordToggleLayout_passwordToggleTint);
}
mPasswordToggleSize = a.getDimensionPixelSize(
R.styleable.PasswordToggleLayout_passwordToggleSize,
(int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
DEFAULT_DRAWABLE_SIZE, getResources().getDisplayMetrics()));
a.recycle();
applyPasswordToggleTint();
}
private void setEditText(EditText editText) {
// If we already have an EditText, throw an exception
if (mEditText != null) {
throw new IllegalArgumentException(
"We already have an EditText, can only have one");
}
mEditText = editText;
final boolean hasPasswordTransformation = hasPasswordTransformation();
updatePasswordToggleView();
}
private void updatePasswordToggleView() {
if (mEditText == null) {
// If there is no EditText, there is nothing to update
return;
}
if (shouldShowPasswordIcon()) {
if (mPasswordToggleView == null) {
// Keep ratio
double w = mPasswordToggleDrawable.getIntrinsicWidth();
double h = mPasswordToggleDrawable.getIntrinsicHeight();
double scale = mPasswordToggleSize / Math.max(w,h);
int scaled_width = (int) (w * scale);
int scaled_height = (int) (h * scale);
FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.WRAP_CONTENT,
FrameLayout.LayoutParams.WRAP_CONTENT,
Gravity.CENTER_VERTICAL | Gravity.END | Gravity.RIGHT);
FrameLayout.LayoutParams lp2 = new FrameLayout.LayoutParams(
scaled_width, scaled_height, Gravity.CENTER);
mPasswordToggleViewGroup = new FrameLayout(this.getContext());
mPasswordToggleViewGroup.setMinimumWidth(mButtonMinSize);
mPasswordToggleViewGroup.setMinimumHeight(mButtonMinSize);
mPasswordToggleViewGroup.setLayoutParams(lp);
mInputFrame.addView(mPasswordToggleViewGroup);
mPasswordToggleViewGroup.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
passwordVisibilityToggleRequested(false);
}
});
mPasswordToggleView = new CheckableView(this.getContext());
mPasswordToggleView.setBackground(mPasswordToggleDrawable);
mPasswordToggleView.setContentDescription(mPasswordToggleContentDesc);
mPasswordToggleView.setLayoutParams(lp2);
mPasswordToggleViewGroup.addView(mPasswordToggleView);
}
if (mEditText != null && ViewCompat.getMinimumHeight(mEditText) <= 0) {
// We should make sure that the EditText has the same min-height
// as the password toggle view. This ensure focus works properly,
// and there is no visual jump if the password toggle is enabled/disabled.
mEditText.setMinimumHeight(
ViewCompat.getMinimumHeight(mPasswordToggleViewGroup));
}
mPasswordToggleViewGroup.setVisibility(VISIBLE);
mPasswordToggleView.setChecked(mPasswordToggledVisible);
// Need to add a dummy drawable as the end compound drawable so that
// the text is indented and doesn't display below the toggle view.
if (mPasswordToggleDummyDrawable == null) {
mPasswordToggleDummyDrawable = new ColorDrawable();
}
// Important to use mPasswordToggleViewGroup, as mPasswordToggleView
// wouldn't replicate the margin of the default-drawable.
mPasswordToggleDummyDrawable.setBounds(
0, 0, mPasswordToggleViewGroup.getMeasuredWidth(), 1);
final Drawable[] compounds = TextViewCompat.getCompoundDrawablesRelative(mEditText);
// Store the user defined end compound drawable so that we can restore it later
if (compounds[2] != mPasswordToggleDummyDrawable) {
mOriginalEditTextEndDrawable = compounds[2];
}
TextViewCompat.setCompoundDrawablesRelative(mEditText, compounds[0],
compounds[1], mPasswordToggleDummyDrawable, compounds[3]);
// Copy over the EditText's padding so that we match
mPasswordToggleViewGroup.setPadding(mEditText.getPaddingLeft(),
mEditText.getPaddingTop(), mEditText.getPaddingRight(),
mEditText.getPaddingBottom());
} else {
if (mPasswordToggleViewGroup != null
&& mPasswordToggleViewGroup.getVisibility() == VISIBLE) {
mPasswordToggleViewGroup.setVisibility(View.GONE);
}
if (mPasswordToggleDummyDrawable != null) {
// Make sure that we remove the dummy end compound drawable if
// it exists, and then clear it
final Drawable[] compounds = TextViewCompat.getCompoundDrawablesRelative(mEditText);
if (compounds[2] == mPasswordToggleDummyDrawable) {
TextViewCompat.setCompoundDrawablesRelative(mEditText,
compounds[0], compounds[1],
mOriginalEditTextEndDrawable, compounds[3]);
mPasswordToggleDummyDrawable = null;
}
}
}
}
private void applyPasswordToggleTint() {
if (mPasswordToggleDrawable != null && mHasPasswordToggleTintList) {
mPasswordToggleDrawable = DrawableCompat.wrap(mPasswordToggleDrawable).mutate();
DrawableCompat.setTintList(mPasswordToggleDrawable, mPasswordToggleTintList);
if (mPasswordToggleView != null
&& mPasswordToggleView.getBackground() != mPasswordToggleDrawable) {
mPasswordToggleView.setBackground(mPasswordToggleDrawable);
}
}
}
private void passwordVisibilityToggleRequested(boolean shouldSkipAnimations) {
if (mPasswordToggleEnabled) {
// Store the current cursor position
final int selection = mEditText.getSelectionEnd();
if (hasPasswordTransformation()) {
mEditText.setTransformationMethod(null);
mPasswordToggledVisible = true;
} else {
mEditText.setTransformationMethod(PasswordTransformationMethod.getInstance());
mPasswordToggledVisible = false;
}
mPasswordToggleView.setChecked(mPasswordToggledVisible);
if (shouldSkipAnimations) {
mPasswordToggleView.jumpDrawablesToCurrentState();
}
// And restore the cursor position
mEditText.setSelection(selection);
}
}
private boolean hasPasswordTransformation() {
return mEditText != null
&& mEditText.getTransformationMethod() instanceof PasswordTransformationMethod;
}
private boolean shouldShowPasswordIcon() {
return mPasswordToggleEnabled && (hasPasswordTransformation() || mPasswordToggledVisible);
}
#Override
public void addView(View child, int index, final ViewGroup.LayoutParams params) {
if (child instanceof EditText) {
// Make sure that the EditText is vertically at the bottom,
// so that it sits on the EditText's underline
FrameLayout.LayoutParams flp = new FrameLayout.LayoutParams(params);
flp.gravity = Gravity.CENTER_VERTICAL
| (flp.gravity & ~Gravity.VERTICAL_GRAVITY_MASK);
mInputFrame.addView(child, flp);
// Now use the EditText's LayoutParams as our own and update them
// to make enough space for the label
mInputFrame.setLayoutParams(params);
setEditText((EditText) child);
} else {
// Carry on adding the View...
super.addView(child, index, params);
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
updatePasswordToggleView();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
#Override
public Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
SavedState ss = new SavedState(superState);
ss.isPasswordToggledVisible = mPasswordToggledVisible;
return ss;
}
#Override
protected void onRestoreInstanceState(Parcelable state) {
if (!(state instanceof SavedState)) {
super.onRestoreInstanceState(state);
return;
}
SavedState ss = (SavedState) state;
super.onRestoreInstanceState(ss.getSuperState());
if (ss.isPasswordToggledVisible) {
passwordVisibilityToggleRequested(true);
}
requestLayout();
}
static class SavedState extends AbsSavedState {
boolean isPasswordToggledVisible;
SavedState(Parcelable superState) {
super(superState);
}
SavedState(Parcel source, ClassLoader loader) {
super(source, loader);
isPasswordToggledVisible = (source.readInt() == 1);
}
#Override
public void writeToParcel(Parcel dest, int flags) {
super.writeToParcel(dest, flags);
dest.writeInt(isPasswordToggledVisible ? 1 : 0);
}
public static final Creator<SavedState> CREATOR = new ClassLoaderCreator<SavedState>() {
#Override
public SavedState createFromParcel(Parcel in, ClassLoader loader) {
return new SavedState(in, loader);
}
#Override
public SavedState createFromParcel(Parcel in) {
return new SavedState(in, null);
}
#Override
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
public static class CheckableView extends View {
private final int[] DRAWABLE_STATE_CHECKED =
new int[]{android.R.attr.state_checked};
private boolean mChecked;
public CheckableView(Context context) {
super(context);
}
public CheckableView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
}
public CheckableView(Context context, #Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public void setChecked(boolean checked) {
if (mChecked != checked) {
mChecked = checked;
refreshDrawableState();
}
}
#Override
public int[] onCreateDrawableState(int extraSpace) {
if (mChecked) {
return mergeDrawableStates(
super.onCreateDrawableState(extraSpace
+ DRAWABLE_STATE_CHECKED.length), DRAWABLE_STATE_CHECKED);
} else {
return super.onCreateDrawableState(extraSpace);
}
}
}
}
And then in an attrs.xml:
<declare-styleable name="PasswordToggleLayout">
<attr name="passwordToggleEnabled" format="boolean"/>
<attr name="passwordToggleDrawable" format="reference"/>
<attr name="passwordToggleContentDescription" format="string"/>
<attr name="passwordToggleTint" format="color"/>
<attr name="passwordToggleSize" format="dimension"/>
</declare-styleable>

Same issue for me. The problem comes from the gradle material API implementation:
implementation 'com.google.android.material:material:1.1.0'
downgrade to version 1.0.0 fixes the issue:
implementation 'com.google.android.material:material:1.0.0'

Programmatically change one attribute on custom style

I am creating several textviews that all use the same style. I am attempting to use a SeekBar to update the textsize within the Style so it applies to all textviews with a minimal amount of code. I know I can use a SeekBar to set the textsize of the textviews individually but that seems like a lot of work. The problem is that everywhere I look all I find is that you cannot change the style. Is there any other work around besides doing code like below:
Define my textviews
TextView tv1 = (TextView)findViewById(R.id.tv1);
TextView tv2 = (TextView)findViewById(R.id.tv2);
TextView tv3 = (TextView)findViewById(R.id.tv3);
Inside my SeekBar
progress = seekBarProgress;
if(progress == 0)
{
tv1.setTextSize(12);
tv2.setTextSize(12);
tv3.setTextSize(12);
}
if(progress == 1)
{
tv1.setTextSize(14);
tv2.setTextSize(14);
tv3.setTextSize(14);
}
Etc etc..
I would like to be able to change one attribute of a custom style. I cannot change it all together to a different custom style because I am going to do SeekBars for Text size, text color, background color, etc. If I did custom styles for each one there would be TONS.
Since I will have a lot of textviews doing this method seems illogical. Is there a better way? Thanks.
GOT THE ANSWER!
Instead of changing the style I retrieve the child and then the child of that child and change it accordingly like below.
LinearLayout masterLayout = (LinearLayout)findViewById(R.id.masterLayout);
int childCount = masterLayout.getChildCount();
for(int i = 0; i < childCount; i++)
{
LinearLayout innerChild = ((LinearLayout)masterLayout.getChildAt(i));
int childOfChildCount = innerChild.getChildCount();
for(int x = 0; x < childOfChildCount; x++)
{
((TextView)innerChild.getChildAt(x)).setTextSize(30);
}
}

What about group these TextView in only one Layout? Then change it programmatically.
In my example I group all of TextViews in only one LinearLayout.
LinearLayout ll = (LinearLayout) findViewById(R.id.layout);
int childCount = ll.getChildCount();
for (int i=0; i<childCount; i++){
((TextView)ll.getChildAt(i)).setTextSize(20);
}
Be sure that you only have TextViews in your layout.

I know that you have already implemented and accepted a solution, however, I have been thinking about this for a while for myself, and have come up with an alternative, more generic solution which may be of use. This involves four elements
Creating an interface for the style changed events
Creating a handler for the style changed events
Extending TextView to have one or more style changed events
Triggering the style change events
Although this is more code it has the advantages of being independent of layouts, and of the view classes (ie the same handler can be used for different View Classes if you also wanted to change the font size of Buttons, EditTexts etc).
The example below just implements a text size change, but the same technique could be used to implement any other style changes.
The Interface
public interface StyleChange {
void onTextSizeChanged(float size);
}
The Handler
public class TextStyleHandler {
private static TextStyleHandler instance;
private LinkedList<StyleChange> listeners = new LinkedList<>();
public static TextStyleHandler getInstance() {
if (instance == null) instance = new TextStyleHandler();
return instance;
}
public void register(StyleChange item) {
listeners.add(item);
}
public void unregister(StyleChange item) {
listeners.remove(item);
}
public void setTextSize(float f) {
for (StyleChange listener:listeners)
listener.onTextSizeChanged(f);
}
}
The Extended TextView
public class StyledTextView extends TextView implements StyleChange {
public StyledTextView(Context cx) {
super(cx);
init();
}
public StyledTextView(Context cx, AttributeSet attrs) {
super(cx, attrs);
init()
}
public StyledTextView(Context cx, AttributeSet attrs, int defStyle) {
super(cx, attrs, defStyle);
init();
}
private void init() {
// Any other setup here (eg setting the default size
// or getting current value from shared preferences)
TextStyleHandler.getInstance().register(this);
}
public void onTextSizeChanged(float size) {
setTextSize(size);
}
#Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
TextStyleHandler.getInstance().unregister(this);
}
}
Triggering the style change event
This can be done from your activity, and will change the style of all registered views
TextStyleHandler.getInstance().setTextSize(size);

Using invalidate() , java.lang.NullPointerexception

I am currently working on a Connect four game
I have managed to develop the app to point to where the game knows what column the user has selected. I am currently trying to change the colour of the gap to the respective colour of the user (token has been placed).
The problem I am having is when connectfourView.invalidate() is called I get a java.lang.NullPointerexception
Code below
public void tokenPlacement (int index, float xpos) {
int x = 0;
int lowerxpos = (int) (xpos - 10);
int higherxpos = (int) (xpos + 10);
while (x <= 6)
{
if ( lowerxpos <= ((float) (columnselects.get(x).getWidthPos())) && higherxpos >= ((float) (columnselects.get(x).getWidthPos())))
{
Log.d("In IF", Float.toString(x));
Log.d("Looking at the colour", Float.toString(gaps.get(x).getColor()));
gaps.get(x).setColor(-1);
Log.d("After change what is the colour now", Float.toString(gaps.get(x).getColor()));
connectfourView.invalidate();
break;
}
x++;
}
}
About the code. Firstly I know this will only affect the bottom layer of each column's gaps. I will fix this when the colour changing is working. This code is from Gaps.java. This view is ConnectFourView.java (instance connectfourView) where the gaps are drawn to screen. All gaps are stored in a list (gaps) and are defined in the Gap.java (x-postion, colour etc.)
Section from Gap.java
public Gap (int j, int i, int color, double diameter, double widthpos, double heightpos){
this.j = j;
this.i = i;
this.color = color;
this.diameter = diameter;
this.widthpos = widthpos;
this.heightpos = heightpos;
}
public int getJ() {return j;}
public int getI() {return i;}
public int getColor() {return color;}
public void setColor(int newColor) {this.color = newColor;}
public double getDiameter() {return diameter;}
public double getWidthPos() {return widthpos;}
public double getHeightPos() {return heightpos;}
}
This is a question I asked to get to this point
Note that the gaps are added with a button press 'New Game'
If any other information or code is need please leave a comment
Added for dmon:
This is where connectfourView is defined, it has also been imported
public class Gaps {
ConnectFourView connectfourView;
/* Other code, not related to question */
public void tokenplacement()//at bottom of class Gaps
I have noticed that when a click the exit button on the screen all the gaps do change color just before the main menu is loaded, so the problem is just trying to refresh the screen
From ConnectFourView.java
public ConnectFourView(Context context, Gaps gaps) {
super(context);
this.gaps = gaps;
setFocusable(true);
}
//used to mange the attributes of the board (different colour to background for board)
public ConnectFourView(Context context, AttributeSet attrs, Gaps gaps) {
super(context, attrs);
this.gaps = gaps;
setFocusable(true);
setMinimumWidth(getWidth());
setMinimumHeight(getHeight());
}
link to dropbox

As others have said (I gave Henry the bump), connectfourView has to be null there. You need to initialize it:
ConnectFourView connectfourView = new ConnectFourView();
I don't see where that is ever done so it's likely set to null by default.

Android:Why after override onMeasure() in a custom view, the view's text can't show in RalativeLayout?

I made a custom component that extends View and overrides its onMeasure(), the content of this component is some text, then I add it to a RelativeLayout, but this text can't display, if I comment onMeasure() that been overridden the text shows. What's the reason?
Here is the code:
public class CustomView extends View {
private String text;
private int viewWidth;
private int viewHeight;
private Paint paint;
private FontMetrics fontMetrics;
public CustomView(Context context) {
this(context, null);
}
public CustomView(Context context, String text) {
this(context, text, 0);
this.text = text;
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
updateViewBounds();
}
public CustomView(Context context, String text, int defStyle) {
super(context);
}
private void updateViewBounds(){
viewWidth = (int) paint.measureText(this.text);
fontMetrics = paint.getFontMetrics();
viewHeight = (int)(fontMetrics.descent - fontMetrics.ascent);
}
private String getText() {
return this.text;
}
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
setMeasuredDimension(viewWidth, viewHeight);
//setMeasuredDimension(560, 100);even though give a ensured size, it can't //anyway.
}
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
paint.setColor(Color.WHITE);
paint.setTextSize(30);
canvas.drawText(text, 0, 200, paint);
Log.e("content", ""+this.getText());
}
public boolean onTouchEvent (MotionEvent event){
Log.e("Touch", ""+this.getText());
return false;
}
}
Here is the Activity:
public class CustomViewActivity extends Activity {
/** Called when the activity is first created. */
private RelativeLayout contentLayout;
private CustomView view1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
contentLayout = (RelativeLayout)findViewById(R.id.contentLayout);
view1 = new CustomView(this, "You drive me crazy!!!");
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
view1.setLayoutParams(layoutParams);
contentLayout.addView(view1);
}
}
this is the XML file:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/contentLayout"
android:layout_width="1024px"
android:layout_height="560px"
android:orientation="vertical" >
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_marginLeft="126dp"
android:text="Button" />
</RelativeLayout>

You can absolutely set the MeasureSpec to a different size, however, the arguments for onMeasure are misleading. A MeasureSpec is a specially translated int that has to be specifically created by using both a pixel measure and a flag. The correct way to set a specific size it indicated below...
final int desiredHSpec = MeasureSpec.makeMeasureSpec(pixelHeight, MeasureSpec.MODE_CONSTANT);
final int desiredWSpec = MeasureSpec.makeMeasureSpec(pixelWidth, MeasureSpec.MODE_CONSTANT);
setMeasuredDimension(desiredWSpec, desiredHSpec);
The MODE_CONSTANTS must have a value of one of the following:
* AT_MOST - meaning that it is dynamic, but will be clipped if the contents are too large
* EXACTLY - meaning it will be that size no matter how large or small the contents are
* UNSPECIFIED - meaning that it will make whatever decision it makes according to the parameters of the parents, children, device size, etc...
If you do not specify one of these constants, then the Android Layout rendering engine has no idea what to do, and simply hides the object. It must be understood, that as an open platform for so many devices, Google decided to make the layout engine "dynamic and intelligent" to support as many apps as possible on as many platforms as possible. This simply requires the developer to let the device know exactly what it needs.
Note: It sounds like you want EXACTLY, but think carefully about your choice and how many devices you will be supporting. :)

How to create a view similar to the system notification area in android?

I'd like to have a view in my activity, which initially stays at the top of the screen like a little bar, but when you tap on it it should expand down, like the system notification area.
I haven't found any standard controls with such behaviour. What's the best way to implement this?

Use a SlidingDrawer. Here is a good tutorial.

The SlidingDrawer works exactly in this way.

The problem is that the SlidingDrawer can't be positioned at the top of the screen — it opens only upwards (see related question). So I implemented a simple control of my own, using the TranslateAnimation
class MySlidingDrawer extends LinearLayout {
public static final int STATE_OPENED = 0;
public static final int STATE_CLOSED = 1;
private int m_intState;
private LinearLayout m_content;
private ImageButton m_handle;
public MySlidingDrawer(Context context) {
super(context);
setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
setOrientation(VERTICAL);
setGravity(Gravity.CENTER);
m_content = new LinearLayout(context);
// add your content here
addView(m_content);
m_intState = STATE_CLOSED;
m_handle = new ImageButton(context);
m_handle.setImageResource(R.drawable.icon);
m_handle.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
toggleState();
}
});
m_handle.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
addView(m_handle);
}
private int getContentHeight() {
return m_content.getHeight();
}
private void toggleState() {
int intYStart = 0;
int intYEnd = m_intState == STATE_OPENED ? -getContentHeight() : getContentHeight();
Animation a = new TranslateAnimation(0.0f, 0.0f, intYStart, intYEnd);
a.setDuration(1000);
a.setStartOffset(300);
a.setInterpolator(AnimationUtils.loadInterpolator(getContext(), android.R.anim.bounce_interpolator));
startAnimation(a);
m_intState = m_intState == STATE_OPENED ? STATE_CLOSED : STATE_OPENED;
}
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
offsetTopAndBottom(-getContentHeight()); // content is initially invisible
}
protected void onAnimationEnd() {
super.onAnimationEnd();
int intYOffset = m_intState == STATE_OPENED ? getContentHeight() : -getContentHeight();
offsetTopAndBottom(intYOffset);
}
}

You can use the code posted in this answer: Android SlidingDrawer from top?
The provided solution features setting the orientation of the Slidingdrawer in xml also it's simple requiring only 1 class and some additions in attrs.xml and stable since it's derived from Androids Slidingdrawer from SDK. I also discuss why I didn't choose other popular libs/solutions found on the internet/SO.
Quicklink to the gist: MultipleOrientationSlidingDrawer (source & example) # gist