onConfigurationChanged 无法正常工作
onConfigurationChanged isn't working properly
所以我要做的就是检查方向并根据它更改图像。问题是图像没有变化，toast 消息也没有起作用。不知道为什么..我在其他地方也有同样的代码。
Java:
public class Test extends AppCompatActivity {
private ArrayList<String> mNames = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
getText();
}
private void getText() {
mNames.add("Menu");
mNames.add("Definitions");
mNames.add("Steps");
mNames.add("Examples");
mNames.add("Related");
mNames.add("Videos");
initRecyclerView();
}
private void initRecyclerView() {
LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
RecyclerView recyclerView = findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(layoutManager);
RecyclerViewAdapter adapter = new RecyclerViewAdapter(this, mNames);
recyclerView.setAdapter(adapter);
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Checks the orientation of the screen
if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
setContentView(R.layout.activity_main);
Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
ImageView layout = findViewById(R.id.background);
layout.setBackgroundResource(R.drawable.background_l);
} else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
setContentView(R.layout.activity_main);
Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
ImageView layout = findViewById(R.id.background);
layout.setBackgroundResource(R.drawable.background_p);
}
}
}
XML:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto">
<ImageView
android:id="@+id/background"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY" />
<RelativeLayout
android:id="@+id/relativeLayout2"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/recyclerView"
android:paddingTop="5dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="20dp">
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginTop="15dp"
android:fontFamily="@font/open_sans_bold"
android:text="@string/definition"
android:textColor="@color/backgroundBlue"
android:textSize="20sp" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textView2"
android:layout_marginEnd="20dp"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:fontFamily="@font/open_sans"
android:text="@string/fiveSDef1"
android:textColor="@android:color/background_dark"
android:textSize="14sp" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textView3"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:fontFamily="@font/open_sans_bold"
android:text="@string/uses"
android:textColor="@color/backgroundBlue"
android:textSize="20sp" />
<TextView
android:id="@+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textView4"
android:layout_marginEnd="20dp"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:fontFamily="@font/open_sans"
android:text="@string/fiveSDef2"
android:textColor="@android:color/background_dark"
android:textSize="14sp" />
<TextView
android:id="@+id/textView6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textView5"
android:layout_marginEnd="20dp"
android:layout_marginStart="20dp"
android:layout_marginTop="15dp"
android:fontFamily="@font/open_sans"
android:text="@string/fiveSDef3"
android:textColor="@android:color/background_dark"
android:textSize="14sp" />
</RelativeLayout>
</ScrollView>
<Button
android:id="@+id/button2"
android:layout_width="match_parent"
android:layout_height="56dp"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:background="@color/backgroundBlue"
android:fontFamily="@font/open_sans_bold"
android:text="@string/fiveS"
android:textAllCaps="false"
android:textColor="@android:color/white"
android:textSize="29sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteY="0dp" />
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_below="@id/button2"
android:layout_marginTop="15dp"
android:orientation="horizontal" />
</RelativeLayout>
清单：
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:configChanges="orientation|keyboardHidden|screenSize|screenLayout">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".ToolTables.1"></activity>
<activity android:name=".ToolTables.2"
android:windowSoftInputMode="adjustPan">
</activity>
<activity android:name=".ToolTables.3"></activity>
<activity android:name=".ToolTables.4"></activity>
<activity android:name=".ToolTables.5"></activity>
<activity
android:name=".Test"
android:configChanges="orientation|keyboardHidden|screenSize|screenLayout">
</activity>
<meta-data
android:name="preloaded_fonts"
android:resource="@array/preloaded_fonts" />
</application>
编辑：我添加了其余代码。包括与 Java 耦合的 XML。它并不复杂，主要是文本字段和一个 recyclerView。
onConfigurationChanged() 回调只有在我们指定我们将在 activity 标签内的 manifest.xml 上手动管理此更改时才会被调用：
android:configChanges="orientation|screenSize|keyboardHidden"
这表明 activity 不会在设备旋转时重新创建，不推荐这种行为，除非您有正当理由这样做 ，例如youtube API 建议这样做以避免重新创建和重新初始化 YoutubePlayerFragment。
Caution: Handling the configuration change yourself can make it much more difficult to use alternative resources, because the system does not automatically apply them for you. This technique should be considered a last resort when you must avoid restarts due to a configuration change and is not recommended for most applications.
https://developer.android.com/guide/topics/resources/runtime-changes
如果这不是必需的，只是您想在每个方向上都有不同的图像，您可以：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
boolean isLandscape = this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE;
((ImageView)findViewById(R.id.background)).setImageResource(isLandscape ? R.drawable.background_l : R.drawable.background_p);
getText();
}
所以我要做的就是检查方向并根据它更改图像。问题是图像没有变化，toast 消息也没有起作用。不知道为什么..我在其他地方也有同样的代码。
Java:
public class Test extends AppCompatActivity {
private ArrayList<String> mNames = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
getText();
}
private void getText() {
mNames.add("Menu");
mNames.add("Definitions");
mNames.add("Steps");
mNames.add("Examples");
mNames.add("Related");
mNames.add("Videos");
initRecyclerView();
}
private void initRecyclerView() {
LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
RecyclerView recyclerView = findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(layoutManager);
RecyclerViewAdapter adapter = new RecyclerViewAdapter(this, mNames);
recyclerView.setAdapter(adapter);
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Checks the orientation of the screen
if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
setContentView(R.layout.activity_main);
Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
ImageView layout = findViewById(R.id.background);
layout.setBackgroundResource(R.drawable.background_l);
} else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
setContentView(R.layout.activity_main);
Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
ImageView layout = findViewById(R.id.background);
layout.setBackgroundResource(R.drawable.background_p);
}
}
}
XML:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto">
<ImageView
android:id="@+id/background"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY" />
<RelativeLayout
android:id="@+id/relativeLayout2"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/recyclerView"
android:paddingTop="5dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="20dp">
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginTop="15dp"
android:fontFamily="@font/open_sans_bold"
android:text="@string/definition"
android:textColor="@color/backgroundBlue"
android:textSize="20sp" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textView2"
android:layout_marginEnd="20dp"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:fontFamily="@font/open_sans"
android:text="@string/fiveSDef1"
android:textColor="@android:color/background_dark"
android:textSize="14sp" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textView3"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:fontFamily="@font/open_sans_bold"
android:text="@string/uses"
android:textColor="@color/backgroundBlue"
android:textSize="20sp" />
<TextView
android:id="@+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textView4"
android:layout_marginEnd="20dp"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:fontFamily="@font/open_sans"
android:text="@string/fiveSDef2"
android:textColor="@android:color/background_dark"
android:textSize="14sp" />
<TextView
android:id="@+id/textView6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textView5"
android:layout_marginEnd="20dp"
android:layout_marginStart="20dp"
android:layout_marginTop="15dp"
android:fontFamily="@font/open_sans"
android:text="@string/fiveSDef3"
android:textColor="@android:color/background_dark"
android:textSize="14sp" />
</RelativeLayout>
</ScrollView>
<Button
android:id="@+id/button2"
android:layout_width="match_parent"
android:layout_height="56dp"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:background="@color/backgroundBlue"
android:fontFamily="@font/open_sans_bold"
android:text="@string/fiveS"
android:textAllCaps="false"
android:textColor="@android:color/white"
android:textSize="29sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteY="0dp" />
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_below="@id/button2"
android:layout_marginTop="15dp"
android:orientation="horizontal" />
</RelativeLayout>
清单：
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:configChanges="orientation|keyboardHidden|screenSize|screenLayout">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".ToolTables.1"></activity>
<activity android:name=".ToolTables.2"
android:windowSoftInputMode="adjustPan">
</activity>
<activity android:name=".ToolTables.3"></activity>
<activity android:name=".ToolTables.4"></activity>
<activity android:name=".ToolTables.5"></activity>
<activity
android:name=".Test"
android:configChanges="orientation|keyboardHidden|screenSize|screenLayout">
</activity>
<meta-data
android:name="preloaded_fonts"
android:resource="@array/preloaded_fonts" />
</application>
编辑：我添加了其余代码。包括与 Java 耦合的 XML。它并不复杂，主要是文本字段和一个 recyclerView。
onConfigurationChanged() 回调只有在我们指定我们将在 activity 标签内的 manifest.xml 上手动管理此更改时才会被调用：
android:configChanges="orientation|screenSize|keyboardHidden"
这表明 activity 不会在设备旋转时重新创建，不推荐这种行为，除非您有正当理由这样做 ，例如youtube API 建议这样做以避免重新创建和重新初始化 YoutubePlayerFragment。
Caution: Handling the configuration change yourself can make it much more difficult to use alternative resources, because the system does not automatically apply them for you. This technique should be considered a last resort when you must avoid restarts due to a configuration change and is not recommended for most applications. https://developer.android.com/guide/topics/resources/runtime-changes
如果这不是必需的，只是您想在每个方向上都有不同的图像，您可以：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
boolean isLandscape = this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE;
((ImageView)findViewById(R.id.background)).setImageResource(isLandscape ? R.drawable.background_l : R.drawable.background_p);
getText();
}