將字符串顯示在EditText中崩潰應用程序

Question

單擊調用getdeets的按鈕後，我的應用程序崩潰。我不知道爲什麼。

我希望數據被添加，然後在按鈕單擊時保存，然後數據保留在EditText中永久存在，直到它在相同的EditText中更改爲不同的值。那麼這個新價值將永恆。

的logcat：

09-01 04:59:06.890: W/dalvikvm(1710): threadid=1: thread exiting with uncaught exception (group=0x41465700) 
    09-01 04:59:06.930: E/AndroidRuntime(1710): FATAL EXCEPTION: main 
    09-01 04:59:06.930: E/AndroidRuntime(1710): java.lang.IllegalStateException: Could not execute method of the activity 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at android.view.View$1.onClick(View.java:3633) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at android.view.View.performClick(View.java:4240) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at android.view.View$PerformClick.run(View.java:17721) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at android.os.Handler.handleCallback(Handler.java:730) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at android.os.Handler.dispatchMessage(Handler.java:92) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at android.os.Looper.loop(Looper.java:137) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at android.app.ActivityThread.main(ActivityThread.java:5103) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at java.lang.reflect.Method.invokeNative(Native Method) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at java.lang.reflect.Method.invoke(Method.java:525) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at dalvik.system.NativeStart.main(Native Method) 
    09-01 04:59:06.930: E/AndroidRuntime(1710): Caused by: java.lang.reflect.InvocationTargetException 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at java.lang.reflect.Method.invokeNative(Native Method) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at java.lang.reflect.Method.invoke(Method.java:525) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at android.view.View$1.onClick(View.java:3628) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  ... 11 more 
    09-01 04:59:06.930: E/AndroidRuntime(1710): Caused by: java.lang.NullPointerException 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  at com.mikitz.rogsimple.ArmorStatsSP.getdeets(ArmorStatsSP.java:65) 
    09-01 04:59:06.930: E/AndroidRuntime(1710):  ... 14 more 

你會發現，在頂部宣佈TextViews。我試圖將這些設置爲抓取的數據，但它也使應用程序崩潰。 這裏的活動代碼：

package com.mikitz.rogsimple; 

    import android.app.Activity; 
    import android.content.Context; 
    import android.content.Intent; 
    import android.content.SharedPreferences; 
    import android.os.Bundle; 
    import android.view.View; 
    import android.widget.EditText; 
    import android.widget.TextView; 
    import android.widget.Toast; 

    public class ArmorStatsSP extends Activity { 

EditText armorhealthchest, healthchest, abvchest; 
TextView ChestAH, ChestH, ChestABV; 
EditText armorhealthhead, healthheaad, abvhead; 
EditText armorhealthrightarm, healthrightarm, abvrightarm; 
EditText armorhealthleftarm, healthleftarm, abvleftarm; 
EditText armorhealthrightleg, healthrightleg, abvrightleg; 
EditText armorhealthleftleg, healthleftleg, abvleftleg; 
SharedPreferences pref; 
String getAHChest, getHChest, getABVChest; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.armor_stats); 

    armorhealthchest = (EditText) findViewById(R.id.armorhealthchest); 
    healthchest = (EditText) findViewById(R.id.healthchest); 
    abvchest = (EditText) findViewById(R.id.abvchest); 
}  

public void onBackPressed() 
{ 
    SharedPreferences sharedPreferences = getSharedPreferences("Armor_Stats", Context.MODE_PRIVATE); 
    SharedPreferences.Editor editor=sharedPreferences.edit();   
      editor.putString("armorhealthchest", armorhealthchest.getText().toString()); 
      editor.putString("healthchest", healthchest.getText().toString()); 
      editor.putString("abvchest", abvchest.getText().toString()); 
      editor.commit(); 

    Toast.makeText(this, "GREAT SUCCESS!!!!", Toast.LENGTH_LONG).show(); 

    Intent intent = new Intent (this, MainActivity.class); 
     startActivity(intent); 

} 

public void save (View view) 
{ 
    SharedPreferences sharedPreferences = getSharedPreferences("Armor_Stats", Context.MODE_PRIVATE); 
    SharedPreferences.Editor editor=sharedPreferences.edit();   
      editor.putString("armorhealthchest", armorhealthchest.getText().toString()); 
      editor.putString("healthchest", healthchest.getText().toString()); 
      editor.putString("abvchest", abvchest.getText().toString()); 
      editor.commit(); 

    Toast.makeText(this, "GREAT SUCCESS!!!!", Toast.LENGTH_LONG).show(); 
} 

public void getdeets (View view) 
{ 
    getAHChest = pref.getString("armorhealthchest", ""); 
    getHChest = pref.getString("healthchest", ""); 
    getABVChest = pref.getString("abvchest", ""); 
    armorhealthchest.setText(getAHChest); 
    healthchest.setText(getHChest); 
    abvchest.setText(getABVChest); 

} 

}

Answer 1

看來，在getdeets方法pref爲空，所以在onCreate方法來初始化它作爲

pref = getSharedPreferences("Armor_Stats", Context.MODE_PRIVATE);