Google Android官方培训课程中文版(v0.4)----2.6.1. 保存到Preference 代码

SavingKeyValueSets.java

package com.demo.webb.savingkeyvaluesets; 
 
import android.app.Activity; 
import android.content.Context; 
import android.content.SharedPreferences; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.TextView; 
import android.widget.Toast; 
 
 
public class SavingKeyValueSets extends Activity 
 
    { 
 
    private Button save,read; 
    private TextView textView; 
    private EditText editText; 
    private SharedPreferences pref; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
 
        read = (Button)findViewById(R.id.button_read); 
        save = (Button)findViewById(R.id.button_save); 
 
        textView = (TextView)findViewById(R.id.textView); 
        editText = (EditText)findViewById(R.id.editText); 
 
/*        Retrieve and hold the contents of the preferences file 'name', returning a SharedPreferences 
        through which you can retrieve and modify its values. Only one instance of the SharedPreferences 
        object is returned to any callers for the same name, meaning they will see each other's edits as soon as they are made. 
 
        Parameters 
        name    Desired preferences file. If a preferences file by this name does not exist, 
        it will be created when you retrieve an editor (SharedPreferences.edit()) and then 
        commit changes (Editor.commit()). 
                mode    Operating mode. Use 0 or MODE_PRIVATE for the default operation, MODE_WORLD_READABLE 
        and MODE_WORLD_WRITEABLE to control permissions. The bit MODE_MULTI_PROCESS can also be used if multiple processes 
        are mutating the same SharedPreferences file. MODE_MULTI_PROCESS is always on in apps targetting Gingerbread (Android 2.3) and below, 
        and off by default in later versions. 
              MODE_PRIVATE 
              MODE_WORLD_READABLE 
              MODE_WORLD_WRITEABLE 
              MODE_MULTI_PROCESS*/ 
 
        pref = getSharedPreferences("save_key", Context.MODE_PRIVATE); 
    } 
 
    public void read_key(View view) 
        { 
            // 返回key文件存储的Data,如果找不到key文件则返回“The key file DefValues”位置的String 
            String key = pref.getString("key","The key file DefValues"); 
            textView.setText(key); 
 
            System.out.print("save key"); 
 
 
        } 
    public void save_key(View view) 
        { 
            String key = editText.getText().toString(); 
            //Interface used for modifying values in a SharedPreferences object. All changes you make in an editor are batched, 
            // and not copied back to the original SharedPreferences until you call commit() or apply() 
            SharedPreferences.Editor editor = pref.edit(); 
            editor.putString("key", key); 
            editor.commit(); 
 
            Toast.makeText(SavingKeyValueSets.this, R.string.save_success, Toast.LENGTH_SHORT).show(); 
 
 
        } 
}