Question

所以基本上我想使用xml布局，但我也想要一个画布，我可以在其中执行图形。我所做的是在我的xml布局中查看，如下所示。然后在我的应用程序中我使视图绘制画布，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还是什么。所以，请看看我的代码并告诉我你是否看到了快速修复或者你有更好的方法。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>

这是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);
        }
    }

}

}

Answer 1

从这里开始（这也需要你的输入以及命名空间部分“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TheSurface

中

实施可忽略的例程：

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!!!
}

这应该可以完成你的绘图!!!

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，并且它不需要实现runnable !!!

Answer 2

我不是百分百肯定我明白你要做什么，而是基于你在调用View.draw（）后似乎没有对画布做任何事情的事实我相信你可能是困惑。 View.draw（Canvas）将View绘制到Canvas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，这是一种不太正确的方式，而不是实现自己的视图：

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);
        }
    }

android使用XML布局中的View来绘制画布

2 个答案: