java下面的代码应该打开相机并在我的安卓手机上录制视频。然而，什么也没有发生。有人发现我的代码中有错误吗？

2 周，1 日 Questions & Answers 522

我用这段代码创建（尝试）了一个应用程序，它可以打开相机并开始录制视频，无论是正面还是背面，都无所谓。但无论我尝试过什么，我似乎都无法让它发挥作用。当我按下按钮时，什么都没有发生，没有崩溃，没有新的视图。我不确定是什么问题

package com.example.mediaworld;

import java.io.File;
import java.io.IOException;

import 安卓.app.Activity;
import 安卓.hardware.Camera;
import 安卓.hardware.Camera.Parameters;
import 安卓.media.CamcorderProfile;
import 安卓.media.MediaRecorder;
import 安卓.os.Bundle;
import 安卓.os.Environment;
import 安卓.util.Log;
import 安卓.view.Menu;
import 安卓.view.MenuItem;
import 安卓.view.SurfaceHolder;
import 安卓.view.SurfaceView;
import 安卓.widget.Button;
import 安卓.widget.Toast;

public class MainActivity extends Activity implements SurfaceHolder.Callback {

private SurfaceHolder surfaceHolder;
private SurfaceView surfaceView;
public MediaRecorder mrec = new MediaRecorder();
private Button startRecording = null;
//private button stopRecording;
File video;
private Camera mCamera;

@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Log.i(null, "Video starting");
    startRecording = (Button)findViewById(R.id.buttonstart);
    mCamera = Camera.open();
    surfaceView = (SurfaceView)findViewById(R.id.surfaceView1);
    surfaceHolder = surfaceView.getHolder();
    surfaceHolder.addCallback(this);
    surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}

@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);

    menu.add(0,0,0, "StartRecording");
    menu.add(0,1,0, "StopRecording");
    return super.onCreateOptionsMenu(menu);
    //return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.

    //int id = item.getItemId();
    //if (id == R.id.action_settings) {
    //  return true;
    //}

    switch(item.getItemId()){
    case 0: try{
        startRecording();
    }catch(Exception e){
        String message = e.getMessage();
        Log.i(null, "problem Start" + message);
        mrec.release();
    }
    break; 

    case 1:
        mrec.stop();
        mrec.release();
        mrec = null;
        break;

        default:
            break;
    }
    return super.onOptionsItemSelected(item);
}

protected void startRecording() throws IOException{
    mrec = new MediaRecorder();
    mCamera.unlock();

    mrec.setCamera(mCamera);

    mrec.setPreviewDisplay(surfaceHolder.getSurface());
    mrec.setVideoSource(MediaRecorder.VideoSource.CAMERA);
    mrec.setAudioSource(MediaRecorder.AudioSource.MIC);

    mrec.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));
    mrec.setPreviewDisplay(surfaceHolder.getSurface());
    mrec.setOutputFile("/sdcard/zzzz/3gp");


    mrec.prepare();
    mrec.start();
}

protected void stopRecording(){
    mrec.stop();
    mrec.release();
    mCamera.release();
}

private void releaseMediaRecorder(){
    if(mrec != null){
        mrec.reset();
        mrec.release();
        mrec = null;
        mCamera.lock();
    }
}

private void releaseCamera(){
    if(mCamera != null){
        mCamera.release();
        mCamera = null;
    }
}



@Override
public void surfaceCreated(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    if(mCamera != null){
        Parameters params = mCamera.getParameters();
        mCamera.setParameters(params);
    }else{
        Toast.makeText(getApplicationContext(), "Camera not available!", Toast.LENGTH_LONG).show();
        finish();
    }
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    // TODO Auto-generated method stub

}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    mCamera.stopPreview();
    mCamera.release();
}
}

这是舱单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
package="com.example.mediaworld"
安卓:versionCode="1"
安卓:versionName="1.0" >

<uses-sdk
    安卓:minSdkVersion="14"
    安卓:targetSdkVersion="21" />

<uses-permission 安卓:name="安卓.permission.RECORD_AUDIO" />
<uses-permission 安卓:name= "安卓.permission.CAMERA"/>
<uses-permission 安卓:name="安卓.permission.WRITE_EXTERNAL_STORAGE" />


<application
    安卓:allowBackup="true"
    安卓:icon="@drawable/ic_launcher"
    安卓:label="@string/app_name"
    安卓:theme="@style/AppTheme" >
    <activity
        安卓:name=".MainActivity"
        安卓:label="@string/app_name" >
        <intent-filter>
            <action 安卓:name="安卓.intent.action.MAIN" />

            <category 安卓:name="安卓.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>

以下是主要活动的xml文件：

<LinearLayout xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
xmlns:tools="http://schemas.安卓.com/tools"
安卓:layout_width="fill_parent"
安卓:layout_height="fill_parent"
安卓:orientation="vertical"
安卓:paddingBottom="@dimen/activity_vertical_margin"
安卓:paddingLeft="@dimen/activity_horizontal_margin"
安卓:paddingRight="@dimen/activity_horizontal_margin"
安卓:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.mediaworld.MainActivity" >

<SurfaceView
    安卓:id="@+id/surfaceView1"
    安卓:layout_width="match_parent"
    安卓:layout_height="match_parent"
    安卓:layout_weight="1" />

<Button
    安卓:id="@+id/buttonstart"
    style="?安卓:attr/buttonStyleSmall"
    安卓:layout_width="wrap_content"
    安卓:layout_height="wrap_content"
    安卓:layout_alignParentBottom="true"
    安卓:layout_centerHorizontal="true"
    安卓:layout_marginBottom="50dp"
    安卓:text="Start Rec" />



</LinearLayout>

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java下面的代码应该打开相机并在我的安卓手机上录制视频。然而，什么也没有发生。有人发现我的代码中有错误吗？

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