Question

我正在实施相机应用程序。我从相机捕获图像并将其保存到DCIM文件夹中并将图像显示到ImageView中。图像成功存储到DCIM文件夹中，但不会在全屏尺寸的ImageView中显示。而且我的应用程序崩溃并且出现错误

Uri selectedImageUri = data.getData（）;是空对象引用。

这是我的代码

public class MainActivity extends ActionBarActivity {
    Button b1,b2;
    ImageView iv;private File output=null;int CONTENT_REQUEST =9999;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        b1=(Button)findViewById(R.id.button);
        iv=(ImageView)findViewById(R.id.imageView);

        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v)
            {
                Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
                File dir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);

                output = new File(dir, "CameraContentDemo.jpeg");

                intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(output));
                startActivityForResult(intent, CONTENT_REQUEST);
            }
        });
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);
       // Bitmap bmp = BitmapFactory.decodeFile(urImageFilePath);
        if (requestCode == CONTENT_REQUEST)
        {
            if (resultCode == RESULT_OK)
            {
                try{
                    Uri selectedImageUri  = data.getData();
                    Log.e("selectedImageUri "," = " + selectedImageUri);
                    if(selectedImageUri!=null){

                        Bitmap bmp= BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImageUri));
                        Log.e("bmp "," = " + bmp);
                        iv.setImageBitmap(bmp);
                        Log.e("bmp ", " Displaying Imageview WIth Bitmap !!!!  = ");
                    }
                }
                catch (FileNotFoundException fe)
                {
                    fe.printStackTrace();
                }
            }}

这是Menifest.xml文件中的相机权限

<uses-feature android:name="android.hardware.camera"/>
<uses-permission android:name="android.permission.CAMERA"/>

这是我的Logcat错误

  java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=9999, result=-1, data=null} to activity {com.example.tazeen.demo3/com.example.tazeen.demo3.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.net.Uri android.content.Intent.getData()' on a null object reference
            at android.app.ActivityThread.deliverResults(ActivityThread.java:3568)
            at android.app.ActivityThread.handleSendResult(ActivityThread.java:3611)
            at android.app.ActivityThread.access$1400(ActivityThread.java:147)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1345)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5254)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:898)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.net.Uri android.content.Intent.getData()' on a null object reference
            at com.example.tazeen.demo3.MainActivity.onActivityResult(MainActivity.java:55)
            at android.app.Activity.dispatchActivityResult(Activity.java:6135)
            at android.app.ActivityThread.deliverResults(ActivityThread.java:3564)
            at android.app.ActivityThread.handleSendResult(ActivityThread.java:3611)
            at android.app.ActivityThread.access$1400(ActivityThread.java:147)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1345)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5254)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:898)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
11-23 15:10:34.367     647-1092/? E/ActivityManager﹕ Invalid thumbnail dimensions: 384x384

Answer 1

这是因为data.getData()中不会出现从相机意图中获取的位图，如果您选择了已存在于磁盘中的文件，那么data.getData()将是文件资源的URI。从Camera活动中获取的图片不会被存储，而是在内存中保存为Bitmap，并在intent的附加内容中传递给父活动的onActivityResult，你得到这个位图的方式是这样的

data.getExtras().get("data");

所以代码的变化就是这个，

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);
       // Bitmap bmp = BitmapFactory.decodeFile(urImageFilePath);
        if (requestCode == CONTENT_REQUEST)
        {
            if (resultCode == RESULT_OK)
            {
                try{
                    Uri selectedImageUri  = data.getData();
                    Log.e("selectedImageUri "," = " + selectedImageUri);
                    if(selectedImageUri!=null){

                        Bitmap bmp= BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImageUri));
                        Log.e("bmp "," = " + bmp);
                        iv.setImageBitmap(bmp);
                        Log.e("bmp ", " Displaying Imageview WIth Bitmap !!!!  = ");
                    } else {
                        // If selectedImageUri is null check extras for bitmap
                        Bitmap bmp = (Bitmap) data.getExtras().get("data");
                        iv.setImageBitmap(bmp);
                    }
                }
                catch (FileNotFoundException fe)
                {
                    fe.printStackTrace();
                }
            }}

编辑1

这就是你为结果启动相机活动的意图

final int CHOOSE_CAMERA = 232;
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CHOOSE_CAMERA);

Android：图像不显示在Image-view From Camera中

1 个答案: