I am programming a android app with ImageView and when I try to change the width and height dynamically, the app stops (abort). I am using the following commands:
RelativeLayout.LayoutParams icon_horizontal = new RelativeLayout.LayoutParams(50, 50);
mec21h_icon2.setLayoutParams(icon_horizontal);
The layout is Relative, so what is wrong?
It would be nice to have a Stack trace in order to understand what the error is.
Without this, I can just guess:
you're trying to use the wrong parent layout params
the ImageView ref is null
...
I guess you are trying to change the image dimensions after it is visible (already displayed), if so you should first call for method requestLayout();
i.e.
mImageView.requestLayout();
Re-size image on Click of a button.
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/rel"
tools:context="com.testingpp.scannerbarcode.MainActivity">
<ImageView
android:id="#+id/imageview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:onClick="button_one"
android:src="#drawable/btn_back"
/>
</FrameLayout>
MainActivity.java
public class MainActivity extends AppCompatActivity {
FrameLayout layout;
ImageView imageView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageView = (ImageView) findViewById(R.id.imageview);
layout = (FrameLayout) findViewById(R.id.rel);
}
public void button_one(View view)
{
FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(50,50);
layout.setLayoutParams(params);
}
}
if you are using Framents, then don't use onClick of xml. use onClickListener in java.
Related
I'm trying to resize ImageView on button click. I don't know why but setLayoutParams works when I call it in onCreate method, but not working when use it inside button's OnClickListener. Did I miss something?
ImageView myImageView;
Button myButton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_result);
myImageView = findViewById(R.id.viewtest);
myButton = (Button)findViewById(R.id.buttontest);
resizeImageView(); // resize when called here
myButton.setOnClickListener(new Button.OnClickListener() {
#Override
public void onClick(View v) {
resizeImageView(); // NOT resize when called here
}
});
}
private void resizeImageView() {
Toast.makeText(getApplicationContext(), "Resize", Toast.LENGTH_LONG).show();
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams)myImageView.getLayoutParams();
params.height = 300;
params.width = 300;
myImageView.setLayoutParams(params);
}
XML layout. I'm using LinearLayout inside of RelativeLayout.
<?xml version="1.0" encoding="utf-8"?>
<android.widget.RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ResultActivity">
<android.widget.LinearLayout
android:id="#+id/lineartest"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<ImageView
android:id="#+id/viewtest"
android:layout_width="50dp"
android:layout_height="50dp"
android:scaleType="centerCrop"
android:layout_centerVertical="true"
app:srcCompat="#mipmap/ic_launcher_round"
android:background="#444"
/>
</android.widget.LinearLayout>
<android.support.v7.widget.AppCompatButton
android:id="#+id/buttontest"
android:layout_width="match_parent"
android:layout_height="100dp"
android:text="test"/>
</android.widget.RelativeLayout>
I just checked. This works fine in case of ImageView.
Maybe you are resizing it multiple times. Means If you have already called resresizeImageView() in onCreate method and you call it again in OnClick method , the resizing won't be visible because it already has the size you are resizing to.
In xml, you have AppCompatButton but in java you have defined as Button. Change AppCompatButton to Button in xml Or in java, Button to AppCompatButton.
I used your code, to create a new project, and just commented out the first call to resizeImageView() and it works fine when resizeImageView() is called in onClick()
As Derek answered, maybe you're already setting the same bounds to the ImageView during onCreate() which you wish to update in button click.
Also, just a suggestion:
Try adding the property android:layout_below="#id/lineartest" to your AppCompatButton.
Change android:layout_height="wrap_content", so you can view the changes happening to the ImageView.
Try this one
public class SomeActivity extends Activity {
public static final float screenWidth;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.the_company);
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
screenWidth = metrics.widthPixels;
}
}
And after declare this implementation:
Button mButton = (Button) findViewById(R.id.button);
mButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
float scale = SomeActivity.screenWidth / view.getWidth();
if(view.getScaleX() == 1) {
view.setScaleY(scale);
view.setScaleX(scale);
} else{
view.setScaleY(1);
view.setScaleX(1);
}
}
});
OK. I've found solution. I use some async task that affects ImageView (loading image). When I disabled it resize button started to work as excepted. Thanks for your help.
With the following Java and XML code, I was wondering how to retrieve the dimensions in pixels of an inner/child layout (LinearLayout, whereas the parent is RelativeLayout with paddings of 20dp) properly:
Java code:
public class TestActivity extends Activity {
private LinearLayout linLay;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
linLay = (LinearLayout)findViewById(R.id.linLay);
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT,
RelativeLayout.LayoutParams.MATCH_PARENT);
linLay.setLayoutParams(lp);
getDimensions();
}
private void getDimensions() {
System.out.println(linLay.getHeight());
System.out.println(linLay.getWidth());
}
}
XML:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="20dp" >
<LinearLayout
android:id="#+id/linLay"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true">
</LinearLayout>
</RelativeLayout>
... Since I get outputs of 0 for the dimensions, I am aware that the LinearLayout needs to be set first on the screen before I could retrieve the dimensions... But what am I doing wrong here?
It didn't get its dimensions at the time you try to output them.You can just add a delay or just use method below.
private void getDimensions() {
ViewTreeObserver vto = linLay.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener(){
#Override
public voidonGlobalLayout() {
linLay.getViewTreeObserver().removeGlobalOnLayoutListener(this);
int height =linLay.getMeasuredHeight();
int width =linLay.getMeasuredWidth();
System.out.println(height);
System.out.println(width);
}
});
}
I have a basic app working, but now I am focusing on formatting the app and running into difficulty laying things out as I want them.
I have a list of images that the user can switch from one to the next with using a next button. Both the images and the next button are added programmatically to the page (I clear out anything in the layout, and then add the ImageView and Button). Now, instead of laying them out one on top of the other, I am trying to lay them out next to each other, so the image will take up most of the space, and then the next button will be to its right.
Looking through the documentation I was leaning towards using a RelativeLayout to accomplish this. However, I ran into some questions while using RelativeLayouts programmatically.
Activity.xml
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:fillViewport="true">
<RelativeLayout
android:orientation="vertical"
android:id="#+id/activity_training_package_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:context="com.example.xxx.PackageActivity"
tools:ignore="MergeRootFrame">
</RelativeLayout>
</ScrollView>
Attempt to programmatically add the button:
public void addNextButton(final int currentFile, final RelativeLayout layout) {
Button next = new Button(this);
next.setWidth(100);
int id = layout.getChildAt(0).getId(); // the image is the only thing there
RelativeLayout.LayoutParams lay = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
lay.addRule(RelativeLayout.RIGHT_OF, id);
next.setLayoutParams(lay);
next.setText("NEXT >>");
next.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
showNextFile(currentFile, layout);
}
//layout.setLayoutParams(lay);
layout.addView(next);
...
I am just wondering which LayoutParams I am supposed to be setting for this, the LayoutParams of the layout, or of the view? When I try to set it to the layout, I get a cast exception (it is expecting a FrameLayout.LayoutParams, not a RelativeLayout.LayoutParams for some reason).
Could someone please point me in the right direction to figure out how layouts are used? I cannot seem to find resources that explain which LayoutParams I should be setting.
TL;DR How do you use RelativeLayouts and LayoutParams programmatically?
The simplest solution is to use the HorizontalSrollView with a LinearLayout.
activity_test.xml
<HorizontalScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<LinearLayout
android:id="#+id/container"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="horizontal" />
</HorizontalScrollView>
TestActivity.java
public class TestActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
LinearLayout container = (LinearLayout)findViewById(R.id.container);
ViewGroup.LayoutParams params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
String next = getResources().getString(R.string.next);
for(int i=0;i<5;i++){
ImageView imgView = new ImageView(mActivity);
imgView.setLayoutParams(params);
imgView.setImageResource(R.drawable.photo);
container.addView(imgView);
Button button = new Button(mActivity);
button.setLayoutParams(params);
button.setText(next);
container.addView(button);
}
}
}
set Linear Layout weight Property in your XML file and assign weight to the imageview and button
main_activity.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_vertical"
android:orientation="horizontal"
android:weightSum="1" />
MainActivity.java
package com.example.stackoverflowdemos;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TableLayout;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout container = (LinearLayout)findViewById(R.id.container);
//Dynamically generate imageview and button
ImageView imgView = new ImageView(this);
imgView.setLayoutParams(new TableLayout.LayoutParams(0, LayoutParams.FILL_PARENT, .2f)); //set imageview height and width using weight
imgView.setImageResource(R.drawable.ic_launcher);
container.addView(imgView);
Button button = new Button(this);
button.setLayoutParams(new TableLayout.LayoutParams(0, LayoutParams.WRAP_CONTENT, .8f)); //set Button height and width using weight
button.setText("next");
container.addView(button);
}
}
I am trying to have two images on tp of each other. I can have it work fine with an xml file but I would like to do this dynamically. ctdeasyone is a transparent image.
So this works fine..
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageView
android:id="#+id/bck1"
android:src="#drawable/fish2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:layout_gravity="center">
</ImageView>
<ImageView
android:id="#+id/bck2"
android:src="#drawable/ctdeasyone"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:layout_gravity="center">
</ImageView>
</RelativeLayout>
When I do this. only the second image shows up (it is the transparent one.) Can any of the experts advice on this? Newbbie here... This is my first question. TIA.
public class TwoPicksOnEachOther extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Grabbing the Application context
final Context context = getApplication();
RelativeLayout relativeLayout = new RelativeLayout(this);
final ImageView iv = new ImageView(this);
iv.setImageResource(R.drawable.fish2);
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.FILL_PARENT,
RelativeLayout.LayoutParams.FILL_PARENT);
relativeLayout.addView(iv,lp);
// Creating transparent image
final ImageView iv2 = new ImageView(this);
iv.setImageResource(R.drawable.ctdeasytwo);
RelativeLayout.LayoutParams lp2 = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.FILL_PARENT,
RelativeLayout.LayoutParams.FILL_PARENT);
relativeLayout.addView(iv2,lp2);
setContentView(relativeLayout);
}
}
I had to put it in the emulator and play with it for a while until I saw it:
iv.setImageResource(R.drawable.fish2);
(...)
iv.setImageResource(R.drawable.ctdeasytwo);
You're never setting the image resource for iv2!
I changed that and now I see two images as expected.
This is perfect for FrameLayout . Since you want the images right on top of each other.
I want to show two views in one activity. If I clicked on button in the first view I want to see the second and other way round.
The views should not have the same size as the screen so I want e.g. to center it, like you see in first.xml.
But if I add the views with
addContentView(mFirstView, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
the views are not centered. They are shown at top left.
How can I use the xml settings to e.g. center it?
first.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_height="wrap_content" android:layout_width="wrap_content"
android:background="#drawable/background"
android:layout_gravity="center"
android:minWidth="100dp"
android:minHeight="100dp"
android:paddingBottom="5dp"
>
<LinearLayout android:id="#+id/head"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageButton android:id="#+id/first_button"
android:src="#drawable/show_second"
android:layout_gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#null" />
</LinearLayout>
second.xml same as first.xml but with
<ImageButton android:id="#+id/second_button"
android:src="#drawable/show_first"
... />
ShowMe.java
public class ShowMe extends Activity {
View mFirstView = null;
View mSecondView = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
initFirstLayout();
initSecondLayout();
showFirst();
}
private void initFirstLayout() {
LayoutInflater inflater = getLayoutInflater();
mFirstView = inflater.inflate(R.layout.first, null);
getWindow().addContentView(mFirstView, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
ImageButton firstButton = (ImageButton)mMaxiView.findViewById(R.id.first_button);
firstButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
ShowMe.this.showSecond();
}
});
}
private void initSecondLayout() {
// like initMaxiLayout()
}
private void showFirst() {
mSecondView.setVisibility(View.INVISIBLE);
mFirstView.setVisibility(View.VISIBLE);
}
private void showSecond() {
mFirstView.setVisibility(View.INVISIBLE);
mSecondView.setVisibility(View.VISIBLE);
}}
Hope someone can help.
Thanks
Why don't you use setContentView(R.layout.yourlayout)? I believe the new LayoutParams you're passing in addContentView() are overriding those you defined in xml.
Moreover, ViewGroup.LayoutParams lacks the layout gravity setting, so you would have to use the right one for the layout you're going to add the view to (I suspect it's a FrameLayout, you can check with Hierarchy Viewer). This is also a general rule to follow. When using methods that take layout resources as arguments this is automatic (they might ask for the intended parent).
With this consideration in mind, you could set your layout params with:
FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(/* wrap wrap */);
lp.setGravity(Gravity.CENTER);
addContentView(mYourView, lp);
But I would recommend setContentView() if you have no particular needs.
EDIT
I mean that you create a layout like:
~~~/res/layout/main.xml~~~
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="....."
android:id="#+id/mainLayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
then in your onCreate() or init...Layout():
setContentView(R.layout.main);
FrameLayout mainLayout = (FrameLayout)findViewById(R.id.mainLayout);
// this version of inflate() will automatically attach the view to the
// specified viewgroup.
mFirstView = inflater.inflate(R.layout.first, mainLayout, true);
this will keep the layout params from xml, because it knows what kind it needs. See reference.