8.1 Android Basic 数据存储 Preferences SharedPreferences Demo2

Source code

SharePreferences Demo2

   

• 新建项目PreferDemo, 编辑res/layout/main.xml布局文件：

  <?xml version="1.0" encoding="utf-8"?>

  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

  android:orientation="vertical" android:layout_width="fill_parent"

  android:layout_height="fill_parent">

  <CheckBox android:text="This checkbox is: unchecked"

  android:id="@+id/check"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"></CheckBox>

  <Button android:text="Close"

  android:id="@+id/close"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"></Button>

  </LinearLayout>

  2. 编辑PreferDemo类，按如下代码修改：

  import android.app.Activity;

  import android.content.SharedPreferences;

  import android.os.Bundle;

  import android.view.View;

  import android.widget.Button;

  import android.widget.CheckBox;

  import android.widget.CompoundButton;

  import android.widget.CompoundButton.OnCheckedChangeListener;

     

  public class PrefsDemo extends Activity {

  /** Called when the activity is first created. */

  private CheckBox cb;

  @Override

  public void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  setContentView(R.layout.main);

  cb = (CheckBox)findViewById(R.id.check);

  cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {

  @Override

  public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

  // TODO Auto-generated method stub

  if(isChecked){

  cb.setText("CheckBox是选中的");

  }else{

  cb.setText("CheckBox没有选中");

  }

  }

  });

  Button btn = (Button)findViewById(R.id.close);

  btn.setOnClickListener(new Button.OnClickListener(){

  @Override

  public void onClick(View v) {

  // TODO Auto-generated method stub

  finish();

  }

  });

  }

     

  @Override

  protected void onPause() {

  // TODO Auto-generated method stub

  super.onPause();

  SharedPreferences settings = getPreferences(0);

  SharedPreferences.Editor editor = settings.edit();

  editor.putBoolean("cb_checked", cb.isChecked());

  editor.commit();

  }

     

  @Override

  protected void onResume() {

  // TODO Auto-generated method stub

  super.onResume();

  SharedPreferences settings = getPreferences(0);

  cb.setChecked(settings.getBoolean("cb_checked", false));

  }

  }

     

  在onPause()方法中使用getPreferences()方法获取 SharedPreferences对象。使用SharedPreferences.Editor.edit()方法打开编辑状态，将checkbox的状态使用putBoolean()方法写入。 最后使用commit()方法提交。

  在onResume()方法中获取写入的值。

     

  

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