我是 Android 新手，在尝试启动打开相机、制作照片然后裁剪结果的应用程序时出现此错误。
我会附上一些代码，也许你可以帮助我
谢谢
$java代码
public class MainActivity extends Activity implements OnClickListener {
//keep track of camera capture intent
final int CAMERA_CAPTURE = 1;
//keep track of cropping intent
final int PIC_CROP = 2;
//captured picture uri
private Uri picUri;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//retrieve a reference to the UI button
Button captureBtn = (Button)findViewById(R.id.picture);
//handle button clicks
captureBtn.setOnClickListener(this);
}
/**
* Click method to handle user pressing button to launch camera
*/
public void onClick(View v) {
if (v.getId() == R.id.picture) {
try {
//use standard intent to capture an image
Intent captureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
//we will handle the returned data in onActivityResult
startActivityForResult(captureIntent, CAMERA_CAPTURE);
}
catch(ActivityNotFoundException anfe){
//display an error message
String errorMessage = "Whoops - your device doesn't support capturing images!";
Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT);
toast.show();
}
}
}
/**
* Handle user returning from both capturing and cropping the image
*/
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK) {
//user is returning from capturing an image using the camera
if(requestCode == CAMERA_CAPTURE){
//get the Uri for the captured image
picUri = data.getData();
//carry out the crop operation
performCrop();
}
//user is returning from cropping the image
else if(requestCode == PIC_CROP){
//get the returned data
Bundle extras = data.getExtras();
//get the cropped bitmap
Bitmap thePic = extras.getParcelable("data");
//retrieve a reference to the ImageView
ImageView picView = (ImageView)findViewById(R.id.picture);
//display the returned cropped image
picView.setImageBitmap(thePic);
}
}
}
/**
* Helper method to carry out crop operation
*/
private void performCrop(){
//take care of exceptions
try {
//call the standard crop action intent (the user device may not support it)
Intent cropIntent = new Intent("com.android.camera.action.CROP");
//indicate image type and Uri
cropIntent.setDataAndType(picUri, "image/*");
//set crop properties
cropIntent.putExtra("crop", "true");
//indicate aspect of desired crop
cropIntent.putExtra("aspectX", 1);
cropIntent.putExtra("aspectY", 1);
//indicate output X and Y
cropIntent.putExtra("outputX", 256);
cropIntent.putExtra("outputY", 256);
//retrieve data on return
cropIntent.putExtra("return-data", true);
//start the activity - we handle returning in onActivityResult
startActivityForResult(cropIntent, PIC_CROP);
}
//respond to users whose devices do not support the crop action
catch(ActivityNotFoundException anfe){
//display an error message
String errorMessage = "Whoops - your device doesn't support the crop action!";
Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT);
toast.show();
}
}
}
$xml 主要活动
<?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" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/intro"
android:layout_margin="3dp"
android:textStyle="bold" />
<Button
android:id="@+id/capture_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/capture"
/>
<ImageView
android:id="@+id/picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="@string/picture"
android:layout_margin="5dp"
android:background="@drawable/pic_border" />
</LinearLayout>
$xml 字符串
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="intro">Capture a picture to crop!</string>
<string name="app_name">Shoot And Crop</string>
<string name="picture">Picture</string>
<string name="capture">Launch Camera</string>
</resources>
来自drawable的$xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:dither="true">
<gradient
android:startColor="#99ffffff"
android:endColor="#99ffffff"
android:centerColor="#00000000"
android:angle="90" />
<padding android:left="10dp" android:top="10dp"
android:right="10dp" android:bottom="10dp" />
<corners android:radius="5dp" />
<stroke
android:width="2dp"
android:color="#ccffffff"
/>
</shape>
泰
LOGCAT
04-14 14:48:04.590: D/AndroidRuntime(894): Shutting down VM
04-14 14:48:04.602: W/dalvikvm(894): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-14 14:48:04.720: E/AndroidRuntime(894): FATAL EXCEPTION: main
04-14 14:48:04.720: E/AndroidRuntime(894): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.camera/com.example.camera.MainActivity}: java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.Button
04-14 14:48:04.720: E/AndroidRuntime(894): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.os.Handler.dispatchMessage(Handler.java:99)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.os.Looper.loop(Looper.java:137)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-14 14:48:04.720: E/AndroidRuntime(894): at java.lang.reflect.Method.invokeNative(Native Method)
04-14 14:48:04.720: E/AndroidRuntime(894): at java.lang.reflect.Method.invoke(Method.java:511)
04-14 14:48:04.720: E/AndroidRuntime(894): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-14 14:48:04.720: E/AndroidRuntime(894): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-14 14:48:04.720: E/AndroidRuntime(894): at dalvik.system.NativeStart.main(Native Method)
04-14 14:48:04.720: E/AndroidRuntime(894): Caused by: java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.Button
04-14 14:48:04.720: E/AndroidRuntime(894): at com.example.camera.MainActivity.onCreate(MainActivity.java:32)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.app.Activity.performCreate(Activity.java:5104)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-14 14:48:04.720: E/AndroidRuntime(894): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-14 14:48:04.720: E/AndroidRuntime(894): ... 11 more
04-14 14:53:50.511: D/AndroidRuntime(1027): Shutting down VM
04-14 14:53:50.511: W/dalvikvm(1027): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-14 14:53:50.531: E/AndroidRuntime(1027): FATAL EXCEPTION: main
04-14 14:53:50.531: E/AndroidRuntime(1027): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.camera/com.example.camera.MainActivity}: java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.Button
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.os.Handler.dispatchMessage(Handler.java:99)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.os.Looper.loop(Looper.java:137)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-14 14:53:50.531: E/AndroidRuntime(1027): at java.lang.reflect.Method.invokeNative(Native Method)
04-14 14:53:50.531: E/AndroidRuntime(1027): at java.lang.reflect.Method.invoke(Method.java:511)
04-14 14:53:50.531: E/AndroidRuntime(1027): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-14 14:53:50.531: E/AndroidRuntime(1027): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-14 14:53:50.531: E/AndroidRuntime(1027): at dalvik.system.NativeStart.main(Native Method)
04-14 14:53:50.531: E/AndroidRuntime(1027): Caused by: java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.Button
04-14 14:53:50.531: E/AndroidRuntime(1027): at com.example.camera.MainActivity.onCreate(MainActivity.java:32)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.app.Activity.performCreate(Activity.java:5104)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-14 14:53:50.531: E/AndroidRuntime(1027): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-14 14:53:50.531: E/AndroidRuntime(1027): ... 11 more
04-14 14:53:53.302: I/Process(1027): Sending signal. PID: 1027 SIG: 9