Develop Reference

Create a custom view programatically in Android

When I try to create my GameView, I get an error "function call expected".
in my Main activity:
GameView gv = GameView(this, null);
public class GameView extends View {
private Drawable mCustomImage;
public GameView(Context context, AttributeSet attrs) {
super(context, attrs);
mCustomImage = context.getResources().getDrawable(R.drawable.bg);
}
protected void onDraw(Canvas canvas) {
Rect imageBounds = canvas.getClipBounds(); // Adjust this for where you want it
mCustomImage.setBounds(imageBounds);
mCustomImage.draw(canvas);
}
}
}
How do I create this dynamically?
I'm trying to add a view to my activity. The GameView will then control the position of its subviews programmatically.

This will make scene
I made some new changes in your GameView class. Below is copy of new GameView class.
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.annotation.Nullable;
import android.support.v4.content.ContextCompat;
import android.util.AttributeSet;
import android.view.View;
public class GameView extends View {
private Context mContext;
private Drawable mCustomImage;
public GameView(Context context) {
super(context);
mContext = context;
mCustomImage = ContextCompat.getDrawable(context, R.mipmap.ic_launcher);
}
public GameView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
mContext = context;
mCustomImage = ContextCompat.getDrawable(context, R.mipmap.ic_launcher);
}
public GameView(Context context, #Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mContext = context;
mCustomImage = ContextCompat.getDrawable(context, R.mipmap.ic_launcher);
}
public GameView(Context context, #Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
mContext = context;
mCustomImage = ContextCompat.getDrawable(context, R.mipmap.ic_launcher);
}
#Override
protected void onDraw(Canvas canvas) {
Rect imageBounds = canvas.getClipBounds();
mCustomImage.setBounds(imageBounds);
mCustomImage.draw(canvas);
}
}
Adding it through xml inside activity.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<LinearLayout
android:id="#+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<GameView
android:layout_width="50dp"
android:layout_height="50dp" />
</LinearLayout>
</ScrollView>
Output
Adding it through code in activity
public class CustomActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_draw_line);
initialiseView();
}
private void initialiseView() {
LinearLayout mLinearLayout = (LinearLayout) findViewById(R.id.linearLayout);
GameView mGameView = new GameView(this);
mLinearLayout.addView(mGameView);
}
}
Output
EDIT
If you want to set parameters while adding it pragmatically then initialiseView method will be like
private void initialiseView() {
LinearLayout mLinearLayout = (LinearLayout) findViewById(R.id.linearLayout);
GameView mGameView = new GameView(this);
ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(50, 50);
mGameView.setLayoutParams(layoutParams);
mLinearLayout.addView(mGameView);
}
Output :

GameView is a class, not a method, so you must call new to use them,
try this:
GameView gv = new GameView(this, null);
public class GameView extends View {
private Drawable mCustomImage;
public GameView(Context context, AttributeSet attrs) {
super(context, attrs);
mCustomImage = context.getResources().getDrawable(R.drawable.bg);
}
....

Use new GameView(this, null); inside onCreate of your activity to create a new instance of your view.
Then use the method setContentView(View) to use it in your activity.
public class MainActivity extends AppCompatActivity{
private GameView gameView;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
gameView = new GameView(this, null);
setContentView(gameView);
//other code
}
//other methods
}

Android - CustomView - java.lang.IllegalStateException: Surface was not locked

I'm trying to draw a rectangle over camera2 textureview, when i run the code I see the usual camera screen with moving square , and when I Click (touch) it, app crashes with the error in topic. I also not sure I implemented the custom view correctly, Here are all the relevant parts, Would love some help (I'm not sure I have a good layout xml, I added ViewGroup code under OnCrearte, not sure i even need to touch xml)
-------CameraActivity.java:
package com.example.android.camera2video;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.ViewGroup;
public class CameraActivity extends Activity {
private Context context;
CustomView customview;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
customview = new CustomView(this);
final ViewGroup viewGroup = (ViewGroup) ((ViewGroup) this.findViewById(android.R.id.content)).getChildAt(0);
viewGroup.addView(new CustomView(this));
if (null == savedInstanceState) {
getFragmentManager().beginTransaction()
.replace(R.id.container, Camera2VideoFragment.newInstance())
.commit();
}
}
}
-------CustomView.java
package com.example.android.camera2video;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.os.Handler;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class CustomView extends SurfaceView {
private Paint paint;
private SurfaceHolder mHolder;
private Context context;
public CustomView(Context context) {
super(context);
mHolder = getHolder();
mHolder.setFormat(PixelFormat.TRANSPARENT);
this.context = context;
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.WHITE);
paint.setStyle(Paint.Style.STROKE);
}
public CustomView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// real work here
}
private void doAdditionalConstructorWork() {
// init variables etc.
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
invalidate();
if (mHolder.getSurface().isValid()) {
final Canvas canvas = mHolder.lockCanvas();
Log.d("touch", "touchRecieved by camera");
System.err.println("EXIT 1");
if (canvas != null) {
Log.d("touch", "touchRecieved CANVAS STILL Not Null");
canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
canvas.drawColor(Color.TRANSPARENT);
canvas.drawCircle(event.getX(), event.getY(), 100, paint);
mHolder.unlockCanvasAndPost(canvas);
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
Canvas canvas1 = mHolder.lockCanvas();
if(canvas1 !=null){
canvas1.drawColor(0, PorterDuff.Mode.CLEAR);
mHolder.unlockCanvasAndPost(canvas1);
}
}
}, 1000);
}
mHolder.unlockCanvasAndPost(canvas);
}
}
return false;
}
}
-----fragment_camera2_video.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.example.android.camera2video.AutoFitTextureView
android:id="#+id/texture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true" />
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:layout_below="#id/texture"
android:background="#4285f4">
<Button
android:id="#+id/video"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="#string/record" />
<ImageButton
android:id="#+id/info"
android:contentDescription="#string/description_info"
style="#android:style/Widget.Material.Light.Button.Borderless"
android:layout_width="4dp"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical|right"
android:padding="20dp"
android:src="#drawable/ic_action_info" />
</FrameLayout>
</RelativeLayout>

Only one thing can be drawing to a View at a time; once the SurfaceView is connected to the camera, you're not able to lock it for drawing yourself.
Your crash is probably because you're calling mHolder.unlockCanvasAndPost(canvas); outside of the null check.
If you want to draw over the cameara preview, you need a second View positioned on top of the SurfaceView.

Custom LinearLayout, child is not viewing

I'm creating my Cell view by extending LinearLayout, it's creating parent, but not showing children. I really couldn't find the problem?
Cell cell = new Cell(ctx);
cell.setLetterAndPosition(new Point(1,1), new Letter("A");
import android.content.Context;
import android.graphics.Color;
import android.graphics.Point;
import android.util.AttributeSet;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import android.widget.TextView;
import pe.kor.kelime.Model.Letter;
import pe.kor.kelime.R;
/**
* Created by me on 7/29/15.
*/
public class Cell extends LinearLayout {
private Letter letter;
private Point position; /* 0-3 / 0-3 based position*/
private TextView text;
private boolean touched = false;
public Cell(Context context) {
super(context);
init(context);
}
public Cell(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public Cell(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
public void setLetterAndPosition(Point position, Letter letter) {
this.letter = letter;
this.position = position;
this.text.setText(letter.getLetter());
}
void init(Context context) {
LayoutInflater.from(context).inflate(R.layout.view_cell, this);
text = (TextView) this.findViewById(R.id.text);
this.setBackgroundColor(Color.parseColor("#ffffff"));
}
public Letter getLetterObject() {
return letter;
}
public void setTouched(boolean e) {
this.touched = e;
if(this.touched) {
this.setBackgroundColor(Color.parseColor("#ff0000"));
}
else {
this.setBackgroundColor(Color.parseColor("#ffffff"));
}
}
public boolean isTouched() {
return touched;
}
public Point getPositionInBoard() {
return position;
}
}
View_cell.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5.5dp"
android:clickable="true">
<TextView
android:id="#+id/text"
android:layout_width="60dp"
android:layout_height="60dp"
android:background="#ff0369"
android:baselineAligned="false"
android:clickable="true"
android:gravity="center|center_vertical"
android:includeFontPadding="false"
android:text="A"
android:textColor="#000"
android:textSize="36sp"
android:textStyle="bold"/>
</LinearLayout>

I had to override onLayout method.
onLayout(boolean paramBoolean, int left, int top, int right, int bottom)
#Override
protected void onLayout(boolean paramBoolean, int left, int top, int right, int bottom)
{
int widthOfCell = right - left;
getChildAt(0)
.layout(1,
1,
widthOfCell,
widthOfCell
);
}

I think that the problem is your Textview. You have not added the textview to your linearlayout.
Change your method init
void init(Context context) {
LayoutInflater.from(context).inflate(R.layout.view_cell, this);
text = (TextView) this.findViewById(R.id.text);
this.addView(text);
this.setBackgroundColor(Color.parseColor("#ffffff"));
}

SurfaceView failed to instantiate

I'm trying to implement a custom SurfaceView in my activity's XML file, and then reference it within the activity's code for drawing etc. However, I'm getting the following error:
The following classes could not be instantiated:
- com.example.animateddrawable.MainActivity.DrawingPanel
MainActivity Code:
package com.example.animateddrawable;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.content.Context;
...
com.example.animateddrawable.MainActivity.DrawingPanel.PanelThread;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
dp = new DrawingPanel(this, null);
setContentView(R.layout.activity_main);
}
public class DrawingPanel extends SurfaceView implements SurfaceHolder.Callback {
public DrawingPanel( Context context, AttributeSet attributeSet){
super(context, attributeSet);
init();
}
public void init(){
getHolder().addCallback(this);
}
}
}
XML Code
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" >
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent" >
<com.example.animateddrawable.MainActivity.DrawingPanel
android:id="#+id/surfaceView"
android:layout_width = "fill_parent"
android:layout_height = "fill_parent"/>
</FrameLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" >
</LinearLayout>
Any ideas?

try to add a constructor like this:
public DrawingPanel(Context context) {
super(context);
getHolder().addCallback(this);
}
public DrawingPanel(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
getHolder().addCallback(this);
}
add this to your other constructer as well:
getHolder().addCallback(this);

How to add custom SurfaceView to XML layout

I try to use my own SurfaceView in XML and I am unable to do it. I get NullPointerException.
According internet it should look like this:
Activity:
package editor;
import android.app.Activity;
import android.os.Bundle;
import com.example.balls_menu_v1.R;
public class EditorActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.editor);
EditorView ev = (EditorView) findViewById(R.id.editorView);
}
}
If I comment findViewById I get NullPointerException.
SurfaceView:
package editor;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class EditorView extends SurfaceView {
public EditorView(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public void onFinishInflate() {
super.onFinishInflate();
SurfaceHolder holder = getHolder();
Canvas canvas = holder.lockCanvas();
canvas.drawColor(Color.GREEN);
holder.unlockCanvasAndPost(canvas);
}
}
Layout: editor.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<editor.EditorView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/editorView"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</RelativeLayout>

I found answer: implement SurfaceHolder.Callback, add all 3 constructors of SurfaceView and add getHolder().addCallback(this); to each constructor.
Code:
public class EditorView extends SurfaceView implements SurfaceHolder.Callback{
public EditorView(Context context) {
super(context);
getHolder().addCallback(this);
// TODO Auto-generated constructor stub
}
public EditorView(Context context, AttributeSet attrs) {
super(context, attrs);
getHolder().addCallback(this);
// TODO Auto-generated constructor stub
}
public EditorView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
getHolder().addCallback(this);
// TODO Auto-generated constructor stub
}
public void doDraw() {
SurfaceHolder holder = getHolder();
Canvas canvas = holder.lockCanvas();
canvas.drawColor(Color.GREEN);
holder.unlockCanvasAndPost(canvas);
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {}
#Override
public void surfaceCreated(SurfaceHolder holder) {
doDraw();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
}

you can't call Canvas canvas = holder.lockCanvas();`
before the oncreate flow finish,
you should call it after the oncreate finish