Android 2D图像显示（转）

原文地址：http://blog.csdn.net/Veini/archive/2009/09/10/4537365.aspx
本文介绍在Android如何显示2D图像

1）使用XML，代码如下

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<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/android"
    />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/android"
/>

（代码比较简单，不做解析了！！）

2）继承View

根据public void setContentView (View view) ，新建一个继承View的类，并重写onDraw函数。代码如下：

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.Window;

public class Show2DImage extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        //setContentView(R.layout.main);
        setContentView(new Panel(this));
    }

    class Panel extends View{

  public Panel(Context context) {
   super(context);
   // TODO Auto-generated constructor stub
  }

  public void onDraw(Canvas canvas){
   Bitmap _scratch = BitmapFactory.decodeResource(getResources(), R.drawable.icon);
   canvas.drawColor(Color.BLACK);
   canvas.drawBitmap(_scratch, 10, 10, null);
  }
    }
}

3）利用SurfaceView和Thread

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package android.szu.edu.cn;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;

public class Show2DImage extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        // setContentView(R.layout.main);
        setContentView(new Panel(this));
    }

    // class Panel extends View{
    //
    // public Panel(Context context) {
    // super(context);
    // // TODO Auto-generated constructor stub
    // }
    //
    // public void onDraw(Canvas canvas){
    // Bitmap _scratch = BitmapFactory.decodeResource(getResources(),
    // R.drawable.icon);
    // canvas.drawColor(Color.BLACK);
    // canvas.drawBitmap(_scratch, 10, 10, null);
    // }
    // }

    class Panel extends SurfaceView implements SurfaceHolder.Callback {

        private Draw2DThread _thread;

        public Panel(Context context) {
            super(context);
            getHolder().addCallback(this);
            _thread = new Draw2DThread(getHolder(), this);
        }

        public void onDraw(Canvas canvas) {
            Bitmap _scratch = BitmapFactory.decodeResource(getResources(),
                    R.drawable.android);
            canvas.drawColor(Color.BLACK);
            canvas.drawBitmap(_scratch, 10, 10, null);
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width,
                int height) {
            // TODO Auto-generated method stub

        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            // TODO Auto-generated method stub
            _thread.setRunning(true);
            _thread.start();
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            // TODO Auto-generated method stub
            boolean retry = true;
            _thread.setRunning(false);
            while (retry) {
                try {
                    _thread.join();
                    retry = false;
                } catch (InterruptedException e) {
                    // TODO: handle exception
                }
            }
        }

    }

    class Draw2DThread extends Thread {
        private SurfaceHolder _surfaceHolder;
        private Panel _panel;
        private boolean _run;

        public Draw2DThread(SurfaceHolder surfaceHolder, Panel panel) {
            _surfaceHolder = surfaceHolder;
            _panel = panel;
        }

        public void setRunning(boolean run) {
            _run = run;
        }

        public void run() {
            Canvas c;
            while (_run) {
                c = null;
                try {
                    c = _surfaceHolder.lockCanvas(null);
                    synchronized (_surfaceHolder) {
                        _panel.onDraw(c);
                    }
                } finally {
                    if (c != null) {
                        _surfaceHolder.unlockCanvasAndPost(c);
                    }
                }
            }

        }
    }
}
package android.szu.edu.cn;

public class Show2DImage extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  requestWindowFeature(Window.FEATURE_NO_TITLE);
  // setContentView(R.layout.main);
  setContentView(new Panel(this));
}

// class Panel extends View{
//
// public Panel(Context context) {
// super(context);
// // TODO Auto-generated constructor stub
// }
//
// public void onDraw(Canvas canvas){
// Bitmap _scratch = BitmapFactory.decodeResource(getResources(),
// R.drawable.icon);
// canvas.drawColor(Color.BLACK);
// canvas.drawBitmap(_scratch, 10, 10, null);
// }
// }

class Panel extends SurfaceView implements SurfaceHolder.Callback {

private Draw2DThread _thread;

  public Panel(Context context) {
   super(context);
   getHolder().addCallback(this);
   _thread = new Draw2DThread(getHolder(), this);
  }

  public void onDraw(Canvas canvas) {
   Bitmap _scratch = BitmapFactory.decodeResource(getResources(),
     R.drawable.android);
   canvas.drawColor(Color.BLACK);
   canvas.drawBitmap(_scratch, 10, 10, null);
  }

  @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width,
    int height) {
   // TODO Auto-generated method stub

}

  @Override
  public void surfaceCreated(SurfaceHolder holder) {
   // TODO Auto-generated method stub
   _thread.setRunning(true);
   _thread.start();
  }

  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {
   // TODO Auto-generated method stub
   boolean retry = true;
   _thread.setRunning(false);
   while (retry) {
    try {
     _thread.join();
     retry = false;
    } catch (InterruptedException e) {
     // TODO: handle exception
    }
   }
  }

}

class Draw2DThread extends Thread {
  private SurfaceHolder _surfaceHolder;
  private Panel _panel;
  private boolean _run;

  public Draw2DThread(SurfaceHolder surfaceHolder, Panel panel) {
   _surfaceHolder = surfaceHolder;
   _panel = panel;
  }

  public void setRunning(boolean run) {
   _run = run;
  }

  public void run() {
   Canvas c;
   while (_run) {
    c = null;
    try {
     c = _surfaceHolder.lockCanvas(null);
     synchronized (_surfaceHolder) {
      _panel.onDraw(c);
     }
    } finally {
     if (c != null) {
      _surfaceHolder.unlockCanvasAndPost(c);
     }
    }
   }

}
}
}

第三种方法，可以快速地描绘界面，使用SurfaceView可以让其它非UI线程直接对画面进行操作。

posted on 2010-07-22 23:02 漂漂阅读(889) 评论(0) 编辑收藏引用

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