如何让返回键具有删除编辑内容功能？

[DESCRIPTION]

在编辑界面，如果正在编辑，就删除编辑的内容。如果编辑的内容为空，按下返回键就返回上一界面

请问该如何实现？

[SOLUTION]

修改Activity.java中onKeyUp 为如下：

public boolean onKeyUp(int keyCode, KeyEvent event) {

if (getApplicationInfo().targetSdkVersion

>= Build.VERSION_CODES.ECLAIR) {

if (keyCode == KeyEvent.KEYCODE_BACK && event.isTracking()

&& !event.isCanceled()) {

/// M: Fix ALPS00247686, ALPS00253881 Free test JE issue @{

if (isResumed()) {

View decorView = this.getWindow().getDecorView();//mtkmodifyBegin

if(decorView!=null){

View focus = decorView.findFocus();

if(focus!=null&&focus instanceof EditText){

(EditText) editText = (EditText)focus;

CharSequence text = editText.getText();

if(text!=null && text.length()>0){

editText.clear();

return true;

}

}

}

onBackPressed();//MTKmodify END

return true;

} else {

Log.v(TAG, "Tracking Key Up, activity is resumed: " + isResumed());

// Fix sub activity of tab activity which isn't in resumed state

// Return false means didn't handle this key event

return false;

}

/// @}

}

}

return false;

}

来源：一牛网论坛