Android源码分析（十四）----如何使用SharedPreferencce保存数据

一：SharedPreference如何使用

此文章只是提供一种数据保存的方式， 具体使用场景请根据需求情况自行调整。
EditText添加saveData点击事件， 保存数据。

diff --git a/res/layout/activity_voicemail_settings.xml b/res/layout/activity_voicemail_settings.xml
index cd7af05..57526f2 100755
--- a/res/layout/activity_voicemail_settings.xml
+++ b/res/layout/activity_voicemail_settings.xml
@@ -29,6 +29,7 @@
         android:imeOptions="flagForceAscii|actionDone"
         android:includeFontPadding="true"
         android:inputType="text"
+        android:onClick="saveData"
         android:paddingLeft="@dimen/focus_item_padding_x"
         android:singleLine="true"
         android:textColor="@color/lv_focused"

1. 通过getSharedPreferences("voicemail_data", MODE_PRIVATE);获取SharedPreferen对象。
2. sharedPreferences.edit();获取editor对象。
3. initData()初始化EditText数据。
4. saveData()保存输入数据。
5. mEditText.setSelection(mEditText.getText().length());此方法主要设置EditText光标位置。

diff --git a/src/com/android/settings/VoicemailSettingsActivity.java b/src/com/android/settings/VoicemailSettingsActivity.java
index 9babb18..58e929a 100755
--- a/src/com/android/settings/VoicemailSettingsActivity.java
+++ b/src/com/android/settings/VoicemailSettingsActivity.java
@@ -4,6 +4,7 @@ import android.app.Activity;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
+import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
 import android.os.Bundle;
@@ -12,6 +13,7 @@ import android.view.KeyEvent;
 import android.view.View;
 import android.view.Window;
 import android.widget.EditText;
+import android.widget.Toast;
 
 import java.util.List;
 
@@ -22,6 +24,10 @@ public class VoicemailSettingsActivity extends Activity implements View.OnClic
     private int mSettingsFocusHeight;
     private int mSettingsNormalHeight;
     private int mSettingsStartY;
+    private SharedPreferences sharedPreferences;
+    private SharedPreferences.Editor editor;
+    private String key;
+    private String result;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -33,7 +39,12 @@ public class VoicemailSettingsActivity extends Activity implements View.OnClic
         for (int i = 0; i < ids.length; i++) {
             strs[i] = getString(ids[i]);
         }
+        sharedPreferences = getSharedPreferences("voicemail_data", MODE_PRIVATE);
+        editor = sharedPreferences.edit();
         mEditText = (EditText) findViewById(R.id.input_number);
+        initData();
+        mEditText.setSelection(mEditText.getText().length());//光标行尾
         mSettingsRecyclerView = (SettingsRecyclerView) findViewById(R.id.voicemail_list_view);
         mSettingsAdapter = new SettingsAdapter(this, strs, this);
         mSettingsRecyclerView.setLayoutManager(mSettingsAdapter.getLayoutManager());
@@ -45,6 +56,25 @@ public class VoicemailSettingsActivity extends Activity implements View.OnClic
         mSettingsRecyclerView.setHasFixedSize(true);
     }
 
+    private void initData() {
+        result = sharedPreferences.getString(key, null);
+        if (result == null) {
+            mEditText.setText("");
+        } else {
+            mEditText.setText(result);
+        }
+    }
+
+    public void saveData(View view) {
+        editor.remove(key);
+        String value = mEditText.getText().toString().trim();
+        editor.putString(key, value);
+        editor.commit();
+        Toast.makeText(VoicemailSettingsActivity.this, "save success", Toast.LENGTH_SHORT).show();
+        finish();
+    }
+
+
     @Override
     public void onClick(View view) {
         Log.d("jasun", "=============onClick============");
(END)

---

喜欢源码分析系列可参考其他文章：
Android源码分析（一）-----如何快速掌握Android编译文件
Android源码分析（二）-----如何编译修改后的framework资源文件
Android源码分析（三）-----系统框架设计思想
Android源码分析（四）-----Android源码编译及刷机步骤
Android源码分析（五）-----如何从架构师的角度去设计Framework框架