android - 找不到 id ... fragment PlaceholderFragment 的 View

Question

我有一个简单的应用程序(基于 the Android First App sample )；它唯一做的就是显示一个 EditText 和一个按钮。该按钮创建另一个 Activity ，并显示 EditText 消息……简单! ...但是在模拟器上运行时，当我点击按钮时应用程序关闭并且出现此错误:

"No view found for id 0x7f05003c (com.example.testapp:id/container) for fragment PlaceholderFragment{4173ead8 #0 id=0x7f05003c}"

MainActivity.java

public class MainActivity extends ActionBarActivity {

public final static String EXTRA_MESSAGE = "com.example.testapp.MESSAGE";

public void SendMessage (View view) {
    Intent intent = new Intent(this, DisplayMessageActivity.class);
    EditText editText = (EditText) findViewById(R.id.edt_message);
    String message = editText.getText().toString();
    intent.putExtra(EXTRA_MESSAGE, message);
    startActivity(intent);
}

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

    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment())
                .commit();
    }
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {

    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        return rootView;
    }
}
}

activity_layout.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.testapp.MainActivity"
tools:ignore="MergeRootFrame" />

fragment_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >

<EditText 
    android:id="@+id/edt_message"
    android:layout_weight="1"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:hint="@string/Message" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/textButtom"
    android:onClick="SendMessage" />
</LinearLayout>

DisplayMessageActivity.java

public class DisplayMessageActivity extends ActionBarActivity {

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

    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }

    Intent intent = getIntent();
    String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

    TextView textView = new TextView(this);
    textView.setTextSize (40);
    textView.setText (message);

    setContentView (textView);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_display_message,
                container, false);
        return rootView;
    }
}

}

activity_display_message.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.testapp.DisplayMessageActivity"
tools:ignore="MergeRootFrame" />

fragment_display_message.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >

</RelativeLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.testapp"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="10"
    android:targetSdkVersion="18" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.example.testapp.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
        android:name="com.example.testapp.DisplayMessageActivity"
        android:label="@string/title_activity_display_message"
        android:parentActivityName="com.example.testapp.MainActivity" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.example.testapp.MainActivity" />
    </activity>
</application>

</manifest>

LogCat

> 03-22 11:02:42.755: E/AndroidRuntime(1722):FATAL EXCEPTION: main 03-22
> 11:02:42.755: E/AndroidRuntime(1722):java.lang.RuntimeException:
> Unable to start activity ComponentInfo{com.example.testapp/           
> com.example.testapp.DisplayMessageActivity}:java.lang.IllegalArgumentException:
> No view found for id 0x7f05003c (com.example.testapp:id/container) for
> fragment PlaceholderFragment{417356c8 #0 id=0x7f05003c} 03-22
> 11:02:42.755: E/AndroidRuntime(1722):at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.app.ActivityThread.access$600(ActivityThread.java:141) 03-22
> 11:02:42.755: E/AndroidRuntime(1722):at
> android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.os.Handler.dispatchMessage(Handler.java:99) 03-22
> 11:02:42.755: E/AndroidRuntime(1722):at
> android.os.Looper.loop(Looper.java:137) 03-22 11:02:42.755:
> E/AndroidRuntime(1722):at
> android.app.ActivityThread.main(ActivityThread.java:5103) 03-22
> 11:02:42.755: E/AndroidRuntime(1722):at
> java.lang.reflect.Method.invokeNative(Native Method) 03-22
> 11:02:42.755: E/AndroidRuntime(1722):at
> java.lang.reflect.Method.invoke(Method.java:525) 03-22 11:02:42.755:
> E/AndroidRuntime(1722):at
> com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 03-22
> 11:02:42.755: E/AndroidRuntime(1722):at
> dalvik.system.NativeStart.main(Native Method) 03-22 11:02:42.755:
> E/AndroidRuntime(1722):Caused by: java.lang.IllegalArgumentException:
> No view found for id 0x7f05003c (com.example.testapp:id/container) for
> fragment PlaceholderFragment{417356c8 #0 id=0x7f05003c} 03-22
> 11:02:42.755: E/AndroidRuntime(1722):at
> android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:919)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:570)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1171)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):at
> android.app.Activity.performStart(Activity.java:5143) 03-22
> 11:02:42.755: E/AndroidRuntime(1722):at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
> 03-22 11:02:42.755: E/AndroidRuntime(1722):... 11 more 03-22
> 11:02:42.965: D/dalvikvm(1722): GC_FOR_ALLOC freed 206K, 9% free
> 2808K/3076K, paused 54ms, total 92ms 03-22 11:02:44.764:
> I/Process(1722): Sending signal. PID: 1722 SIG: 9

Answer 1

崩溃是因为setContentView (textView);在 DisplayMessageActivity 中。如果您尝试仅显示您通过 intent 传递的消息，那么您可以直接将 Textview 设置为详细 Activity 的内容。更改 DetailMessageActivity onCreate 如下代码...

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Intent intent = getIntent();
    String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

    TextView textView = new TextView(this);
    textView.setTextSize (40);
    textView.setText (message);

    setContentView (textView);
}

还有一个问题，改变'MainActivity' setContentView(R.layout.activity_layout);