public static final String ACTION_MAIN = "android.intent.action.MAIN";
public static final String ACTION_VIEW = "android.intent.action.VIEW";
public static final String ACTION_EDIT = "android.intent.action.EDIT";
public static final String ACTION_CALL = "android.intent.action.CALL";
public static final String ACTION_CALL_EMERGENCY = "android.intent.action.CALL_EMERGENCY"; 

public Intent(String action);
public Intent(String action, Uri uri);

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

<intent-filter>
　　 <action android:name="com.example.crop_image_my.copper" />
<data android:scheme="crop" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter> 

private void startMyCropIntent(String path) throws FileNotFoundException {
Intent intent = new Intent("com.example.crop_image_my.copper", Uri.parse("crop://" + path));
startActivityForResult(intent, );
} 

if (getIntent().getData() != null) {
imgPath = getIntent().getData().getPath(); // 参见uri的组成形式资料
Log.v("<DBW>", imgPath);
myCropView.setBmpPath(imgPath);
} 

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.btn_crop:
Bitmap croppedImage = myCropView.getCroppedImage();
croppedImageView.setImageBitmap(croppedImage);
saveCroppedImage(croppedImage);
// return to the last activity
Log.v("<DBW>", newFilePath);
getIntent().putExtra("newPath", newFilePath);
setResult(, getIntent());
break;
case R.id.btn_cancel:
setResult();
break;
default:
break;
}
finish();
} 

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case :
if (resultCode == ) {
String path = data.getExtras().getString("newPath");
Log.v("<DBW>", "get------" + path);
Bitmap bmp = BitmapFactory.decodeFile(path);
iv.setImageBitmap(bmp);
} else if (resultCode == ) {
Toast toast = Toast.makeText(this, "您取消了操作", Toast.LENGTH_LONG);
toast.show();
}
break;
default:
break;
}
} 

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity 　　启动显示的
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity　　　　　　　　　　　　　　　　　　　　　　　　切换的
android:name=".ShowMessage"
android:label="@string/title_activity_display_message"
android:parentActivityName=".MainActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.example.android_switchactivity.MainActivity" />
</activity>
</application> 

public final static String EXTRA_MESSAGE = "com.example.android_switchactivity.MESSAGE"; 这个string可以任意赋值，但要保证唯一Intent intent = new Intent(this, ShowMessage.class);
EditText mEt = (EditText)findViewById(R.id.edit_message);
String message = mEt.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent); 

Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
TextView mTv = new TextView(this);
mTv.setTextSize(40);
mTv.setText(message);