android动态添加图层

结果如图

draw_demo_layout.xml

<?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">    <FrameLayout android:orientation="vertical"        android:layout_width="fill_parent" android:layout_height="0dip"         android:id="@+id/sc" android:scrollbars="horizontal"          android:layout_weight="1.0">        <ImageView android:layout_width="fill_parent"             android:layout_height="fill_parent"            android:src="@drawable/image0"            />    </FrameLayout>    <Button android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:text="Draw"        android:onClick="drawHandler"/>    <Button android:layout_width="fill_parent"         android:layout_height="wrap_content" android:text="Clear"        android:onClick="clearHandler"/>     </LinearLayout>

DrawView.java

package xyq.demo;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.View;import android.view.ViewGroup.LayoutParams;import android.widget.LinearLayout;public class DrawView extends View {    public DrawView(Context context) {        super(context);        setLayoutParams(new LayoutParams(LinearLayout.LayoutParams.FILL_PARENT            ,LinearLayout.LayoutParams.FILL_PARENT));     }    public DrawView(Context context, AttributeSet attrs) {        super(context, attrs);    }    @Override     protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        Paint p = new Paint();        p.setColor(Color.RED);        p.setStrokeWidth(5);        canvas.drawLine(50, 50, 100, 150, p);        canvas.drawLine(100, 150, 20, 50, p);    }}

MytesActivity.java

package xyq.demo;import android.app.Activity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.FrameLayout;public class MytesActivity extends Activity {private FrameLayout container;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.draw_demo_layout);        container = (FrameLayout)findViewById(R.id.sc);                container.addView(new DrawView(this));        Log.v("test", ""+container.getChildCount());            }    public void drawHandler(View target){        container.addView(new DrawView(this));        Log.v("test", ""+container.getChildCount());    }    public void clearHandler(View target){        if(container.getChildCount() != 1){            container.removeViewAt(container.getChildCount()-1);        }    }}

源代码

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