【移动应用开发技术】Android Studio屏幕方向以及UI界面状态的示例分析

【移动应用开发技术】AndroidStudio屏幕方向以及UI界面状态的示例分析

package

com.example.orientation;

import

android.os.Bundle;

import

android.util.Log;

import

android.view.View;

import

android.widget.Button;

import

android.widget.TextView;

import

androidx.appcompat.app.AppCompatActivity;

public

class

MainActivity

extends

AppCompatActivity

{

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1.禁止切换横屏：在

AndroidManifest.xml-->application->activity->中设置如下代码（android:screenOrientation="portrait"）

<activity

android:name=".MainActivity"

android:screenOrientation="portrait"

>

2.

创建

Landscape

布局，横屏时，会自动加载

Landscape

的布局界面（清单文件中，注意去掉

android:screenOrientation="portrait"

）

3.

翻转屏幕时，保存窗口控件的状态值;

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*/

Button

button;

TextView

textView;

String

TAG

=

"myTag";

@Override

protected

void

onCreate(Bundle

savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

button

=

findViewById(R.id.button

);

textView

=

findViewById(R.id.textView);

//如果State中的值不为空，如果有相应的这个组件的值，则读取出来赋值上去

if(savedInstanceState

!=null)

{

String

s

=

savedInstanceState.getString("key");

textView.setText(s);

}

button.setOnClickListener(new

View.OnClickListener()

{

@Override

public

void

onClick(View

view)

{

textView.setText(button.getText());

}

});

}

@Override

protected

void

onDestroy()

{

super.onDestroy();

Log.d(TAG,"onDestroy:");

}

@Override

//将

textView

中的值，先保存到

outState

中（键值对）

public

void

onSaveInstanceState(Bundle

outState)

{

super.onSaveInstanceState(outState);

outState.putString("key",textView.getText().toString());

}

}TextView<TextView

android:id="@+id/textview"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:gravity="center"

android:text="This

is

a

TextView"

android:textColor="#00ff00"

android:textSize="24sp"

/>Button<Button

android:id="@+id/button"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="Button"

android:textAllCaps="false"/>EditText<EditText

android:id="@+id/edittext"

android:layout_width="match_parent"