我是
Android编程的初学者,不幸的是我有问题:)
我在我的游戏中有方法writeSettings(),当我想通过readSettings()方法加载最后一个游戏时,我试图保存一些变量来使用它.有一些参数,如第一(第二)PlayerName,第一(第二)Playerscore等.我正在尝试使用SharedPreferences来保存它们,但是在启动程序时我得到“强制关闭”对话框.
@H_502_4@SharedPreferences preferences = getPreferences(MODE_PRIVATE); //Global variable private void writeSettings() { SharedPreferences.Editor editor = preferences.edit(); editor.putInt("timeSave",time); editor.putString("firstPlayerNameSave",firstPlayerNameTextView.getText().toString()); editor.putString("secondPlayerNameSave",secondPlayerNameTextView.getText().toString()); editor.putString("firstPlayerscoreSave",firstPlayerscoreTextView.getText().toString()); editor.putString("secondPlayerscoreSave",secondPlayerscoreTextView.getText().toString()); editor.putInt("nowPlayerSave",nowPlayer); editor.commit(); } private void readSettings() { //"time" parameter program reads in another method firstPlayerNameTextView.setText(preferences.getString("firstPlayerNameSave","")); secondPlayerNameTextView.setText(preferences.getString("secondPlayerNameSave","")); firstPlayerscoreTextView.setText(preferences.getString("firstPlayerscoreSave","")); secondPlayerscoreTextView.setText(preferences.getString("secondPlayerscoreSave","")); nowPlayer = preferences.getInt("nowPlayerSave",-1); }我怎么知道,问题出现在writeSettings()的第一个条目中.
但我不知道我做错了什么？
对不起我的英语不好.
UPD.
@H_502_4@12-23 16:23:31.334: ERROR/AndroidRuntime(410): Uncaught handler: thread main exiting due to uncaught exception 12-23 16:23:31.520: ERROR/AndroidRuntime(410): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.game/com.game.Game}: java.lang.NullPointerException 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2417) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.ActivityThread.access$2200(ActivityThread.java:119) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.os.Handler.dispatchMessage(Handler.java:99) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.os.Looper.loop(Looper.java:123) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.ActivityThread.main(ActivityThread.java:4363) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at java.lang.reflect.Method.invokeNative(Native Method) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at java.lang.reflect.Method.invoke(Method.java:521) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at dalvik.system.NativeStart.main(Native Method) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): Caused by: java.lang.NullPointerException 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.content.ContextWrapper.getPackageName(ContextWrapper.java:120) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.Activity.getLocalClassName(Activity.java:3410) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.Activity.getPreferences(Activity.java:3444) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at com.game.Game.<init>(Game.java:69) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at java.lang.Class.newInstanceImpl(Native Method) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at java.lang.Class.newInstance(Class.java:1479) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.Instrumentation.newActivity(Instrumentation.java:1021) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2409) 12-23 16:23:31.520: ERROR/AndroidRuntime(410): ... 11 moreGame.java:69是SharedPreferences preferences = getPreferences(MODE_PRIVATE);
解决方法
我是这样做的：
@H_502_4@Editor editor = PreferenceManager.getDefaultSharedPreferences(Context).edit();
editor.putString("firstPlayerNameSave",firstPlayerNameTextView.getText().toString());
editor.commit();
阅读：
@H_502_4@firstPlayerNameTextView.setText(PreferenceManager.getDefaultSharedPreferences(Context).getString("firstPlayerNameSave",""));