6

所以基本上我想使用 xml 布局，但我也想要一个可以执行图形的画布。我所做的是在我的 xml 布局中创建一个视图，如下所示。然后在我的应用程序中，我让视图绘制了画布，但它不起作用。我不确定我解决这个问题的方法是完全错误的还是什么。因此，请看一下我的代码，并告诉我您是否看到了快速修复或是否有更好的方法。在此先感谢我真的很感激。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<Button
    android:id="@+id/bTest"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Button" />



<View
    android:id="@+id/vMain"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

</LinearLayout>

那是xml布局

package sm.view.test;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.Button;

public class ViewActivity extends Activity implements OnTouchListener {
/** Called when the activity is first created. */

View v;
Button b;
boolean isRun =true;
SurfaceHolder ourHolder;
Thread ourThread;
Canvas canvas;
boolean isTure = true;
TheSurface ourSurfaceView;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    b= (Button) findViewById(R.id.bTest);
    v = (View) findViewById(R.id.vMain);

    canvas = new Canvas();
    ourSurfaceView = new TheSurface(this);
    ourSurfaceView.setOnTouchListener(this);
    v.draw(canvas);
   // v.setBackgroundColor(Color.BLUE);
}
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    ourSurfaceView.pause();
}

@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();
    ourSurfaceView.resume();
}






public boolean onTouch(View arg0, MotionEvent arg1) {
    // TODO Auto-generated method stub
    return false;
}
public class TheSurface extends SurfaceView implements Runnable{

    public TheSurface(Context context) {
        super(context);
        ourHolder= getHolder();

    }
    public void resume(){
        isRun= true;
        ourThread = new Thread(this);
        ourThread.start();  
    }
    public void pause(){
        isRun = false;
        while(true){
            try {
                ourThread.join();
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            break;
        }
        ourThread= null;
    }

    public void run() {
        // TODO Auto-generated method stub

        Paint textPaint = new Paint();
        textPaint.setColor(Color.WHITE);
        while(isTure){
        if(!ourHolder.getSurface().isValid())
            continue;
        //v.draw(canvas);

         canvas = ourHolder.lockCanvas();
        canvas.drawLine(0, 0, canvas.getWidth(), canvas.getHeight(), textPaint);
        ourHolder.unlockCanvasAndPost(canvas);
        v.draw(canvas);
        }
    }

}

}

4

2 回答 2

1

从这里开始（这也需要您输入命名空间部分“yourProjectNamespace”）：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:orientation="vertical" >  

    <Button android:id="@+id/bTest"
        android:layout_width="wrap_content"     
        android:layout_height="wrap_content"
        android:text="Button" />    

    <sm.view.test.TheSurface android:id="@+id/vMain"
        android:layout_width="wrap_content"     
        android:layout_height="wrap_content" />  

</LinearLayout>

在你的 TheSurface

实现可覆盖的例程：

public TheSurface(Context C){
    super(C);

    // Other setup code you want here
}

public TheSurface(Context C, AttributeSet attribs){
    super(C, attribs);

    // Other setup code you want here
}

public TheSurface(Context C, AttributeSet attribs, int defStyle){
    super(C, attribs, defStyle);

    // Other setup code you want here
}

protected void onDraw(Canvas canvas){
    super.onDraw(canvas);

    Paint textPaint = new Paint();
    textPaint.setColor(Color.WHITE);

    canvas.drawLine(0, 0, canvas.getWidth(), canvas.getHeight(), textPaint);

    // Other drawing functions here!!!
}

这应该可以完成您的绘图！

同样在我的情况下，您不必将其实现为SurfaceView，您可以将其实现为View，并且不需要实现runnable！！！

于 2012-06-22T20:22:20.267 回答
0

我不是 100% 确定我了解您要做什么，但是基于您在调用 View.draw() 后似乎没有对画布做任何事情的事实，我相信您可能会感到困惑。View.draw(Canvas) 将视图绘制到画布上，它不会改变视图。

但是，如果您从位图创建画布，则可以将位图设置为 ImageView 的图像：

Bitmap bm = Bitmap.createBitmap( x-size, y-size, Config.ARGB_8888);
Canvas c = new Canvas(bm);

Paint textPaint = new Paint();
textPaint.setColor(Color.WHITE);
canvas.drawLine(0, 0, canvas.getWidth(), canvas.getHeight(), textPaint);

ImageView iView = (ImageView) view;
iView.setImageBitmap(bm);

但是，与实现您自己的视图相比，这是一种不太正确的方法：

button.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View view) {
            ((MyView)view).mContextVariable = true; //or false, etc
            //you might not need this invalidate, because the click event probably causes and invalidate to be called
            view.invalidate();
        }
    }

    class MyView extends View
    {
        Paint myPaint;
        boolean mContextVariable;

        public MyView(Context context) 
        {
            super(context);

             textPaint = new Paint();
             textPaint.setColor(Color.WHITE);

        }

        @Override
        protected void onDraw(Canvas canvas)
        {
            if(mContextVariable)
            {
                canvas.drawLine(0, 0, canvas.getWidth(), canvas.getHeight(), textPaint);
            }
            else
            {
                //draw something else
            }
            canvas.drawText("testing", 0,0, textPaint);
        }
    }
于 2012-06-26T16:44:35.920 回答