Question

I am trying to call a static method from another activity to find a integer for a score:

public class HighscoreActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.highscore);

        TextView txtGuess = (TextView) findViewById(R.id.txtScore);
        int temp = MastermindGameActivity.getScore();
        String score = Integer.toString(temp);
        txtGuess.setText(score);

    }
}

采用这种方法:

public static int getScore()
{
    return score;
}

Why will this not work? I keep getting

01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): 01-14 21:28:54.347: ERROR/AndroidRuntime(1485): ... 11 more FATAL EXCEPTION: main java.lang.RuntimeException: Unable to start activity ComponentInfo{sam.android.mastermind/sam.android.mastermind.HighscoreActivity}: java.lang.NullPointerException at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) at android.app.ActivityThread.access$1500(ActivityThread.java:117) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:123) at android.app.ActivityThread.main(ActivityThread.java:3683) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:507) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.NullPointerException at sam.android.mastermind.HighscoreActivity.blah(HighscoreActivity.java:27) at sam.android.mastermind.HighscoreActivity.onCreate(HighscoreActivity.java:13) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)

The activity is defined in manifest.

Answer 1

引证。

MastermindGameActivity masterActivity = new MastermindGameActivity();

masterActivity.getScore();

你们也可以尝试把它当作一个建议的意图。

 Intent intent=new Intent(this,Activity2.class);
 intent.putIntExtra("Score" score);

并退出接收活动

 Intent sender=getIntent();
     int score = sender.getExtras().getInt("Score");

友情链接