我的应用程序因消息而崩溃
java.lang.IllegalStateException: Could not execute method of the activity E/AndroidRuntime(6043):at android.view.View$1.onClick(View.java:3823)
这是我的 CameraController类：
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.hardware.Camera.PictureCallback;
import android.os.Environment;
import android.util.Log;
import android.view.SurfaceView;
public class CameraController {
private Context context;
private boolean hasCamera;
private Camera camera;
private int cameraId;
public CameraController(Context c){
context = c;
if(context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
cameraId = getFrontCameraId();
if(cameraId != -1){
hasCamera = true;
}else{
hasCamera = false;
}
}else{
hasCamera = false;
}
}
public boolean hasCamera(){
return hasCamera;
}
public void getCameraInstance(){
camera = null;
if(hasCamera){
try{
camera = Camera.open(cameraId);
prepareCamera();
}
catch(Exception e){
hasCamera = false;
}
}
}
public void takePicture(){
if(hasCamera){
camera.takePicture(null,null,mPicture);
}
}
public void releaseCamera(){
if(camera != null){
camera.stopPreview();
camera.release();
camera = null;
}
}
private int getFrontCameraId(){
int camId = -1;
int numberOfCameras = Camera.getNumberOfCameras();
CameraInfo ci = new CameraInfo();
for(int i = 0;i < numberOfCameras;i++){
Camera.getCameraInfo(i,ci);
if(ci.facing == CameraInfo.CAMERA_FACING_FRONT){
camId = i;
}
}
return camId;
}
private void prepareCamera(){
SurfaceView view = new SurfaceView(context);
try{
camera.setPreviewDisplay(view.getHolder());
}catch(IOException e){
throw new RuntimeException(e);
}
camera.startPreview();
Camera.Parameters params = camera.getParameters();
params.setJpegQuality(100);
camera.setParameters(params);
}
private PictureCallback mPicture = new PictureCallback(){
@Override
public void onPictureTaken(byte[] data, Camera camera){
File pictureFile = getOutputMediaFile();
if(pictureFile == null){
Log.d("TEST", "Error creating media file, check storage permissions");
return;
}
try{
Log.d("TEST","File created");
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
}catch(FileNotFoundException e){
Log.d("TEST","File not found: "+e.getMessage());
} catch (IOException e){
Log.d("TEST","Error accessing file: "+e.getMessage());
}
}
};
private File getOutputMediaFile(){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),"MyCameraApp");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.
// Create the storage directory if it does not exist
if(!mediaStorageDir.exists()){
if(!mediaStorageDir.mkdirs()){
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
mediaFile = new File(mediaStorageDir.getPath()+File.separator+"IMG_"+timeStamp+".jpg");
return mediaFile;
}
}
MainActivity ：
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@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;
}
@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;
}
return super.onOptionsItemSelected(item);
}
public void Onclick(View view)
{
CameraController click = new CameraController(MainActivity.this);
click.takePicture();
}
}
main.xml中
<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.cameraapi.postcamera.MainActivity" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginTop="35dp"
android:onClick="Onclick"
android:text="Make Photo"/>
</RelativeLayout>
LogCat ：
08-14 12:10:15.813: E/AndroidRuntime(7432): FATAL EXCEPTION: main
08-14 12:10:15.813: E/AndroidRuntime(7432): Process: com.cameraapi.postcamera, PID: 7432
08-14 12:10:15.813: E/AndroidRuntime(7432): java.lang.IllegalStateException: Could not execute method of the activity
08-14 12:10:15.813: E/AndroidRuntime(7432): at android.view.View$1.onClick(View.java:3823)
08-14 12:10:15.813: E/AndroidRuntime(7432): at android.view.View.performClick(View.java:4438)
08-14 12:10:15.813: E/AndroidRuntime(7432): at android.view.View$PerformClick.run(View.java:18422)
08-14 12:10:15.813: E/AndroidRuntime(7432): at android.os.Handler.handleCallback(Handler.java:733)
08-14 12:10:15.813: E/AndroidRuntime(7432): at android.os.Handler.dispatchMessage(Handler.java:95)
08-14 12:10:15.813: E/AndroidRuntime(7432): at android.os.Looper.loop(Looper.java:136)
08-14 12:10:15.813: E/AndroidRuntime(7432): at android.app.ActivityThread.main(ActivityThread.java:5034)
08-14 12:10:15.813: E/AndroidRuntime(7432): at java.lang.reflect.Method.invokeNative(Native Method)
08-14 12:10:15.813: E/AndroidRuntime(7432): at java.lang.reflect.Method.invoke(Method.java:515)
08-14 12:10:15.813: E/AndroidRuntime(7432): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-14 12:10:15.813: E/AndroidRuntime(7432): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
08-14 12:10:15.813: E/AndroidRuntime(7432): at dalvik.system.NativeStart.main(Native Method)
08-14 12:10:15.813: E/AndroidRuntime(7432): Caused by: java.lang.reflect.InvocationTargetException
08-14 12:10:15.813: E/AndroidRuntime(7432): at java.lang.reflect.Method.invokeNative(Native Method)
08-14 12:10:15.813: E/AndroidRuntime(7432): at java.lang.reflect.Method.invoke(Method.java:515)
08-14 12:10:15.813: E/AndroidRuntime(7432): at android.view.View$1.onClick(View.java:3818)
08-14 12:10:15.813: E/AndroidRuntime(7432): ... 11 more
08-14 12:10:15.813: E/AndroidRuntime(7432): Caused by: java.lang.NullPointerException
08-14 12:10:15.813: E/AndroidRuntime(7432): at com.cameraapi.postcamera.CameraController.takePicture(CameraController.java:64)
08-14 12:10:15.813: E/AndroidRuntime(7432): at com.cameraapi.postcamera.MainActivity.Onclick(MainActivity.java:41)
08-14 12:10:15.813: E/AndroidRuntime(7432): ... 14 more
一切看起来都很好但仍然发生崩溃而无法弄明白为什么？ 任何人都可以帮助我解决这个问题。
答案 0 :(得分：0)
takePicture()中的NPE。您的camera为空。您尚未调用方法getCameraInstance()，而是在camera对象上CameraController初始化takePicture()。