我的 Activity 名为 BlacklistAddActivity。
UI 元素:EditText editText、Button btn1。当我单击 btn1 时，它将启动联系人列表 Activity ，我可以从联系人列表中选择一个联系人。然后将联系人信息发送回BlacklistAddActivity，并通过editText.setText(contact.name)将联系人的名字设置为text1。
问题是，有时候，在联系人列表中，如果我做了一些操作:从最近的应用程序窗口输入拨号器(长按主页键)，然后调用电话等......正如我们所知，android 将检查内存以决定是否销毁 Activity 堆栈。如果内存不足，它会销毁后台 Activity ，包括 BlacklistActivity。
现在，恢复到联系人列表并选择一个联系人，恢复到 BlacklistActivity，它将被重新创建。我可以在 onActivityResult() 中正确获取联系人信息。然后，editText.setText(contact.name)。奇怪的是:UI上显示的editText还是空的。
以下是我的代码:(不完整)
public class BlacklistAddActivity extends PreferenceActivity implements OnSharedPreferenceChangeListener {
static final boolean DBG = true;
private static final String TAG = "BlacklistAddActivity";
private static final String KEY_MATCH_CRITERIA = "match_criteria";
private SharedPreferences mSharedPreferences;
private ListPreference mCriteria;
private static final int CONTACT_ITEM = 0;
private static final int LOGS_ITEM = 1;
private static final String NUM_PROJECTION[] = { Phone.DISPLAY_NAME, Phone.NUMBER };
protected static final Intent CONTACT_IMPORT_INTENT;
static {
CONTACT_IMPORT_INTENT = new Intent(Intent.ACTION_GET_CONTENT);
CONTACT_IMPORT_INTENT.setType(Phone.CONTENT_ITEM_TYPE);
}
private Context mContext;
private EditText editText;
private ImageButton searchButton;
private TwSoftkeyItem mLeftSoftkey, mRightSoftkey;
private AlertDialog mSearchDialog = null;
private InputMethodManager imm;
private boolean updateMode;
private String mNumber;
private int mMatchCriteria;
@Override
protected void onCreate(Bundle savedInstanceState) {
initTitle();
super.onCreate(savedInstanceState);
Log.i(TAG, "onCreate()");
setContentView(R.layout.blacklist_number_layout);
addPreferencesFromResource(R.xml.blacklist_add_num_prefs);
mSharedPreferences = getPreferenceScreen().getSharedPreferences();
mContext = getBaseContext();
mCriteria = (ListPreference) findPreference(KEY_MATCH_CRITERIA);
editText = (EditText) findViewById(R.id.edit_text);
editText.requestFocus();
searchButton = (ImageButton) findViewById(R.id.search_button);
mLeftSoftkey = (TwSoftkeyItem) findViewById(R.id.skleft);
mRightSoftkey = (TwSoftkeyItem) findViewById(R.id.skright);
initValue();
initEvent();
imm = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
handler.postDelayed(new Runnable() {
public void run() {
imm.showSoftInput(editText, 1);
}
}, 200);
}
private void initTitle() {
String str = getIntent().getStringExtra("FROM");
if (str != null) {
if (DBG) Log.i(TAG, "initTitle() => from: " + str);
if (str.equals("msg")) {
setTitle(R.string.list_msg_block_num);
} else {
setTitle(R.string.list_call_block_num);
}
}
}
private void initValue() {
updateMode = getIntent().getBooleanExtra("UPDATE_MODE", false);
Log.i(TAG, "the updatemode is: "+ updateMode);
if (updateMode == true) { //from Edit
mNumber = getIntent().getStringExtra("NUMBER");
mMatchCriteria = getIntent().getIntExtra("CRITERIA", 0);
editText.setText(mNumber);
editText.setSelection(mNumber.length());
mCriteria.setValueIndex(mMatchCriteria);
mCriteria.setSummary(mCriteria.getEntry());
} else { // from Add
mCriteria.setValueIndex(0);
mCriteria.setSummary(mCriteria.getEntry());
}
}
private void initEvent() {
searchButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
alertDialogSearch();
}
});
editText.setOnFocusChangeListener(new OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean focused) {
if (focused == true) {
handler.postDelayed(new Runnable() {
public void run() {
imm.showSoftInput(editText, 1);
}
}, 200);
} else {
imm.hideSoftInputFromWindow(editText.getWindowToken(), 0);
}
}
});
editText.setOnKeyListener(new OnKeyListener() {
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER && event.getAction() == KeyEvent.ACTION_UP) {
editText.requestFocus();
return true;
}
return false;
}
});
mLeftSoftkey.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent();
intent.putExtra("NUMBER", editText.getText().toString());
intent.putExtra("CRITERIA", mCriteria.findIndexOfValue(mCriteria.getValue()));
setResult(RESULT_OK, intent);
finish();
}
});
mRightSoftkey.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
setResult(RESULT_CANCELED, null);
finish();
}
});
}
@Override
public void onRestoreInstanceState(Bundle savedInstanceState)
{
if(DBG){
if(null != editText)
Log.d(TAG, "onRestoreInstanceState: Edit Text is: "+editText.getText().toString());
}
super.onRestoreInstanceState(savedInstanceState);
if(DBG){
if(null != editText)
Log.d(TAG, "onRestoreInstanceState: Edit Text is: "+editText.getText().toString());
}
}
@Override
protected void onResume() {
super.onResume();
Log.i(TAG, "onResume()");
if(null != editText)
if (DBG) Log.d(TAG, "onResume() Edit Text is: "+editText.getText().toString());
mSharedPreferences.registerOnSharedPreferenceChangeListener(this);
mCriteria.setSummary(mCriteria.getEntry());
}
@Override
protected void onPause() {
super.onPause();
mSharedPreferences.unregisterOnSharedPreferenceChangeListener(this);
if (mSearchDialog != null) {
mSearchDialog.dismiss();
mSearchDialog = null;
}
}
@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
if (DBG) Log.v(TAG, "onSharedPreferenceChanged(), key: " + key);
if (KEY_MATCH_CRITERIA.equals(key)) {
if (mCriteria.getEntry() == null) {
mCriteria.setValueIndex(0);
}
mCriteria.setValue(sharedPreferences.getString(key, mCriteria.getEntry().toString()));
mCriteria.setSummary(mCriteria.getEntry());
if (DBG) Log.v(TAG, "setValue: " + mCriteria.getEntry().toString());
}
}
private Handler handler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 0:
System.out.println("DONE");
break;
}
}
};
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
String output = "";
switch (requestCode) {
case CONTACT_ITEM:
if (resultCode != RESULT_OK) {
Log.e(TAG, "onActivityResult() => canceled");
} else {
Cursor cursor = getContentResolver().query(data.getData(), NUM_PROJECTION, null, null, null);
if (cursor != null) {
if (cursor.moveToFirst()) {
output = cursor.getString(1);
if (DBG) Log.d(TAG, "onActivityResult() => contact output: " + output);
if (Utils.isValidNum(mContext, output)) {
editText.setText(output);
if (DBG) Log.d(TAG, "onActivityResult() Edit Text is: "+editText.getText().toString());
}
}
cursor.close();
}
}
break;
case LOGS_ITEM:
if (resultCode == RESULT_OK) {
output = data.getStringExtra("NUMBER");
if (DBG) Log.d(TAG, "onActivityResult() => logs output: " + output);
if (Utils.isValidNum(mContext, output)) {
editText.setText(output);
} else {
output = null;
Utils.displayToast(mContext, getString(R.string.vip_msg_wrong_number));
}
}
break;
}
handler.postDelayed(new Runnable() {
public void run() {
imm.showSoftInput(editText, 1);
}
}, 200);
if (output != null && output.length() > 0) {
editText.requestFocus();
editText.setSelection(output.length());
}
}
private void alertDialogSearch() {
AlertDialog.Builder ad = new AlertDialog.Builder(this);
ad.setTitle(R.string.title_search).setItems(R.array.dialog_search, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent intent;
switch (which) {
case CONTACT_ITEM:
startActivityForResult(CONTACT_IMPORT_INTENT, CONTACT_ITEM);
break;
case LOGS_ITEM:
intent = new Intent("contacts.com.sec.android.app.dialertab.calllog.LogsListActivity");
intent.putExtra("OPTION", 1);
startActivityForResult(intent, LOGS_ITEM);
break;
}
imm.hideSoftInputFromWindow(editText.getWindowToken(), 0);
}
});
mSearchDialog = ad.show();
}
}
最佳答案
Android 不会在 Activity 被销毁时自动备份任何数据。您必须在数据被销毁之前手动备份数据，并在重新创建 Activity 时将其恢复。
要备份您的数据，您必须覆盖此方法。 (它将在您的 Activity 被销毁之前调用。)
@Override
protected void onSaveInstanceState(Bundle savedInstanceState)
{
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putString("key", value); //save your data in key-value pair
}
要恢复您的数据，您必须覆盖此方法。 (它将在您的 Activity 恢复之前被调用。)
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState)
{
super.onRestoreInstanceState(savedInstanceState);
value = savedInstanceState.getString("key"); //retrieve your data using its corresponding key
}
关于android - EditText 在恢复时不显示任何内容。 (被安卓系统破坏的 Activity )，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10579959/