求助：使用surfaceview 预览camera 的画面都是黑的。

[老特拉福德的荣光]

代码如下所示：

import java.io.IOException;

import android.hardware.Camera;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.Button;

public class MainActivity extends Activity {
private Button takepicture;
private SurfaceView surfaceView=null;
private SurfaceHolder holder;
private Camera camera;
private SurfaceHolder.Callback takeback=new SurfaceHolder.Callback() {
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
//在这里实现将camer中的内容显示到这里面来
camera.open();//打开手机的摄像头
try {
camera.setPreviewDisplay(surfaceView.getHolder()); //将麝香头的类容显示到holder上面去
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
camera.startPreview();//开始展示
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {

}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
findid();
surfaceView=new SurfaceView(MainActivity.this);
surfaceView.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
surfaceView.getHolder().addCallback(takeback);
setContentView(R.layout.activity_main);
}

private void findid() {
// TODO Auto-generated method stub
surfaceView=(SurfaceView) findViewById(R.id.surfaceCammer);
takepicture=(Button) findViewById(R.id.takepicture);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}

[老特拉福德的荣光]

activity_main的内容如下:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity" >

<SurfaceView
android:id="@+id/surfaceCammer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/takepicture"
android:layout_gravity="center_horizontal"
android:text="拍照"
/>
</LinearLayout>

[jklwan]

把setContentView(R.layout.activity_main)放在findid()之前，否则找不到控件。 camera.open();//打开手机的摄像头这一句删除，然后在onCreate(Bundle savedInstanceState)方法中的最后加上camera=Camera.open();

[老特拉福德的荣光]

我照着你这样做了 可是依然是黑屏

[老特拉福德的荣光]

我已经搞出来了 就是不能 写这一句surfaceView=new SurfaceView(MainActivity.this); 之前在findid(）方法中已经实现了findviewbyid() 已经获取了这个surfaceview的实例。ok了谢谢啦

[老特拉福德的荣光]

怪我自己太粗心了