Android编程自定义组件实例详解

package myview;
import com.example.allcode.R;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;
public class MyView extends View{
  public float bitmipx;
  public float bitmipy;
  public MyView(Context context) {
    super(context);
    bitmipx=550;
    bitmipy=550;
    // TODO Auto-generated constructor stub
  }
  @Override
  protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
    super.onDraw(canvas);
    //创建并实例化Paint对象
    Paint paint = new Paint();
    //根据图片生成位图对象
    Bitmap bitmap = BitmapFactory.decodeResource(this.getResources(), R.drawable.image_equip_baibao_baicaodan);
    canvas.drawBitmap(bitmap, bitmipx,bitmipy, paint); //绘制图片
    if(bitmap.isRecycled()) //判断图片是否可以回收
    {
      bitmap.recycle(); //强制回收图片
    }
  }
}

package myview;
import com.example.allcode.R;
import android.app.Activity;
import android.os.Bundle;
import android.provider.ContactsContract.CommonDataKinds.Event;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.FrameLayout;
public class ShowMyView extends Activity{
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.showmyview);
    FrameLayout framelayout = (FrameLayout) findViewById(R.id.showview);
    final MyView myview = new MyView(ShowMyView.this); //创建并示例化MyView类
    //添加触摸事件
    myview.setOnTouchListener(new OnTouchListener() {
      @Override
      public boolean onTouch(View v, MotionEvent event) {
        // TODO Auto-generated method stub
        myview.bitmipx=event.getX();
        myview.bitmipy=event.getY();
        myview.invalidate();//重绘自定义组件
        return true;
      }
    });
    framelayout.addView(myview);
  }
}

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:id="@+id/showview" //不要忘记这一行
   >
</FrameLayout>