Android 如何在特定的 LinearLayout 中添加 Canvas？
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How to add Canvas in a specific LinearLayout?
提问by Nandagopal T
I am new comer to android but not to java. I have been designing UI in android through XML file, in that page i have 3 linear Layouts, in my top layout(first LinearLayout) i have kept some image and in the last layout i have kept some buttons,now i need to place a circle(of red color) in my center layout using canvas,i have written a separate class that extends View where in onDraw(Canvas canvas) ,i have drawn a circle.
我是android的新手，但不是java的新手。我一直在通过 XML 文件在 android 中设计 UI，在那个页面我有 3 个线性布局，在我的顶部布局（第一个 LinearLayout）中我保留了一些图像，在最后一个布局中我保留了一些按钮，现在我需要放置一个圆形（红色）在我的中心布局中使用画布，我编写了一个单独的类来扩展 View ，在 onDraw(Canvas canvas) 中，我画了一个圆圈。
package com.project.TargetTrackr3;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;
public class DrawCanvasCircle extends View{
public DrawCanvasCircle(Context mContext) {
super(mContext);
}
public void onDraw(Canvas canvas) {
Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
canvas.drawColor(Color.WHITE);
paint.setColor(Color.BLUE);
canvas.drawCircle(20, 20, 15, paint);
}
}
Now i have to bring this canvas to the second layout,my main.xml is shown below
现在我必须把这个画布带到第二个布局，我的 main.xml 如下所示
package com.project.TargetTrackr3;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
public class TargetTrackr3Activity extends Activity {
/** Called when the activity is first created. */
protected LinearLayout ll;
DrawCanvasCircle c;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main1); //layouting file
ll = (LinearLayout) findViewById(R.id.LinearLayout_DrawCircle);//This is where i have to bring the canvas
c = new DrawCanvasCircle(this);
...................................
................................
}
}
采纳答案by James Black
Here is what I did to include your view.
这是我为包含您的观点所做的工作。
Start with adding a new layout to your xml file, then you can retrieve that, and then you can add to it like this:
首先向您的 xml 文件添加一个新布局，然后您可以检索它，然后您可以像这样添加到它：
DrawCanvasCircle pcc = new DrawCanvasCircle (this);
Bitmap result = Bitmap.createBitmap(25, 25, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(result);
pcc.draw(canvas);
pcc.setLayoutParams(new LayoutParams(25, 25));
mControls.addView(pcc);
In this example mControlsis a layout that is added to the main activity layout.
在这个例子中mControls是一个添加到主活动布局的布局。
