XML : Android Runtime Exception: Unable to start activity ComponentInfo [duplicate]

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• Unfortunately MyApp has stopped. How can I solve this? 9 answers

I am new to Android Studio and am working on getting a ball responds to tilt. I got some code written down and when I trying to run it, it throws me an error like that. Thanks in advance!

AnimatedView.java

  package com.example.android.ballpls;  import android.content.Context;  import android.graphics.Canvas;  import android.graphics.drawable.BitmapDrawable;  import android.os.Handler;  import android.support.v4.content.ContextCompat;  import android.util.AttributeSet;  import android.widget.ImageView;    public class AnimatedView extends ImageView {  private Context mContext;  int x = -1;  int y = -1;  private int xVelocity = 10;  private int yVelocity = 5;  private Handler h;  private final int FRAME_RATE = 30;    public AnimatedView(Context context, AttributeSet attrs) {      super(context, attrs);      mContext = context;      h = new Handler();  }    private Runnable r = new Runnable() {      @Override      public void run() {          invalidate();      }  };    protected void onDraw(Canvas c) {      BitmapDrawable ball = (BitmapDrawable) ContextCompat.getDrawable(getContext(), R.drawable.ball);      if (x < 0 && y < 0) {          x = this.getWidth() / 2;          y = this.getHeight() / 2;      } else {          x += xVelocity;          y += yVelocity;          if ((x > this.getWidth() - ball.getBitmap().getWidth()) || (x < 0)) {              xVelocity = xVelocity * -1;          }          if ((y > this.getHeight() - ball.getBitmap().getHeight()) || (y < 0)) {              yVelocity = yVelocity * -1;          }      }      c.drawBitmap(ball.getBitmap(), x, y, null);      h.postDelayed(r, FRAME_RATE);  }    

MainActivity.java

  package com.example.android.ballpls;  import android.support.v7.app.AppCompatActivity;  import android.os.Bundle;    public class MainActivity extends AppCompatActivity {    @Override  protected void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.main);  }  }