如何画线以上的ImageView在Android？ [英] How to draw lines over ImageView on Android?
问题描述
我想开发一个简单的地图应用程序，它会显示在屏幕上的地图。
I am trying to develop a simple map application, which will display a map in the screen.
当用户在屏幕上移动光标，我想显示2垂直线在我的地图。我曾试过很多例子让一个想法是，但不幸的是，没能成功。 我怎样才能让这个？
When the user moves the cursor on screen, I want to display 2 perpendicular lines over my map. I had tried many examples to get an idea for that, but unfortunately, didn't succeed. How can I make this?
和为一体previous问题<一href="http://stackoverflow.com/questions/6178896/how-to-draw-a-line-in-imageview-on-android">here我曾尝试。但没有得到答案。任何人都可以指导我？
And as one previous questionhere I had tried. but didn't get the answer. Can anyone guide me?
我的main.xml方法如下：
My main.xml is as following:
<?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" >
<LinearLayout android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView android:id="@+id/main_imagemap"
android:src="@drawable/worldmap"
android:clickable="true"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
</LinearLayout>
和我的活动文件（我刚开始吧..）
And my activity file(i had just started it..)
import android.app.Activity;
import android.os.Bundle;
import android.widget.ImageView;
public class LineMapActivity extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageView map_image = (ImageView)findViewById(R.id.main_imagemap);
}
}
和在该链接，我也加入MyImageView。
And as in that link, i had also added MyImageView.
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.widget.ImageView;
public class MyImageView extends ImageView
{
public MyImageView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
canvas.drawLine(0, 0, 20, 20, p);
super.onDraw(canvas);
}
}
现在我怎么可以添加此MyImageView我的应用程序？
Now how can i add this MyImageView to my app?
推荐答案
最后，我想出了一个解决方案。这是该画线在图像的简单程序。
Finally I figured out a solution. It's a simple program which draws a line over an Image.
下面是我的main.xml文件（com.ImageDraw.MyImageView是我的自定义视图，code以下）：
Here is my main.xml file (com.ImageDraw.MyImageView is my custom view, code below):
<?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" >
<LinearLayout android:layout_width="wrap_content"
android:layout_height="wrap_content">
<com.ImageDraw.MyImageView android:id="@+id/main_imagemap"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
</LinearLayout>
和这里的主要活动：
import android.app.Activity;
import android.os.Bundle;
public class MyActivity extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
这是我的自定义图像视图（MyImageView）：
and this is my custom image view (MyImageView):
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class MyImageView extends SurfaceView implements SurfaceHolder.Callback
{
private CanvasThread canvasthread;
public MyImageView(Context context) {
super(context);
getHolder().addCallback(this);
canvasthread = new CanvasThread(getHolder(), this);
setFocusable(true);
}
public MyImageView(Context context, AttributeSet attrs)
{
super(context,attrs);
getHolder().addCallback(this);
canvasthread = new CanvasThread(getHolder(), this);
setFocusable(true);
}
protected void onDraw(Canvas canvas) {
Log.d("ondraw", "ondraw");
Paint p = new Paint();
Bitmap mapImg = BitmapFactory.decodeResource(getResources(), R.drawable.mybitmap);
canvas.drawColor(Color.BLACK);
canvas.drawBitmap(mapImg, 0, 0, null);
p.setColor(Color.RED);
canvas.drawLine(0, 0, 100, 100, p);
}
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
public void surfaceCreated(SurfaceHolder holder) {
canvasthread.setRunning(true);
canvasthread.start();
}
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
canvasthread.setRunning(false);
while (retry)
{
try
{
canvasthread.join();
retry = false;
}
catch (InterruptedException e) {
// TODO: handle exception
}
}
}
}
最后，这里是我CanvasThread：
And finally here is my CanvasThread:
import android.graphics.Canvas;
import android.view.SurfaceHolder;
public class CanvasThread extends Thread
{
private SurfaceHolder surfaceHolder;
private MyImageView myImageView;
private boolean run = false;
public CanvasThread(SurfaceHolder s, MyImageView m)
{
surfaceHolder = s;
myImageView = m;
}
public void setRunning(boolean r)
{
run = r;
}
public void run()
{
Canvas c;
while(run)
{
c=null;
try
{
c= surfaceHolder.lockCanvas(null);
synchronized (surfaceHolder) {
myImageView.onDraw(c);
}
}
finally
{
if(c!=null)
{
surfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
}
您可以在此教程的详细信息
这篇关于如何画线以上的ImageView在Android？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
