Question

好吧所以我正在制作一个配置文件应用程序，它正在制作一系列问题，并在最后将每个答案添加给它们并为其添加一个值，并为此提供文本结果我使用putExtra以便跟踪结果，但是当我尝试去结果活动它只是崩溃，所有活动都在清单中声明

这是第一个到目前为止一切顺利进行的活动：

package com.springair.perfiladorsam;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class Donde extends Activity implements OnClickListener {
Button cama;
Button litera;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.donde);
    setupVariables();


}

private void setupVariables() {
    // TODO Auto-generated method stub
    Button cama = (Button) findViewById(R.id.cama);
    Button litera = (Button) findViewById(R.id.litera);
  cama.setOnClickListener(this);
  litera.setOnClickListener(this);

}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

    Intent resultado = new Intent ("com.springair.perfilador.RESULTADO");
    Bundle extras = getIntent().getExtras();
    int resulta = extras.getInt("StoredData");

    switch(v.getId()){
    case R.id.Delg:
        resulta = resulta + 5;
        resultado.putExtra("StoredData", (int)resulta);
        startActivity(resultado);

        break;
    case R.id.Medio:
        resulta = resulta + 3;
        resultado.putExtra("StoredData", (int)resulta);
        startActivity(resultado);
        break;

    }
}
}

然后是结果Activity：但它永远不会达到它：

package com.springair.perfiladorsam;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class Resultado extends Activity implements OnClickListener{

    Button reinicio;
    TextView Firmeza;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        setContentView(R.layout.resultado);
        super.onCreate(savedInstanceState);
        setupVariables();
        Bundle extras = getIntent().getExtras();
        int resulta = extras.getInt("StoredData");

        if(resulta<5){
            Firmeza.setText("Firme");
        }
        else if (resulta <10){
            Firmeza.setText("Medio");
        }
        else{
            Firmeza.setText("Suave");
        }
    }

    private void setupVariables() {
        // TODO Auto-generated method stub
        reinicio = (Button)findViewById(R.id.Reinicio);
        Firmeza = (TextView)findViewById(R.id.Nivel);
        reinicio.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        Intent cheese = new Intent("com.springair.perfilador.MAINMENU");
        startActivity(cheese);
    }


}

¿我做错了什么？同样，所有内容都在清单中声明，名称是正确的，我已经检查了两次。

这是LogCat

01-31 23:16:46.684: E/AndroidRuntime(831): java.lang.RuntimeException: Unable to instantiate application android.app.Application: java.lang.NullPointerException
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.app.LoadedApk.makeApplication(LoadedApk.java:504)
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4364)
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.app.ActivityThread.access$1300(ActivityThread.java:141)
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1294)
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.os.Handler.dispatchMessage(Handler.java:99)
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.os.Looper.loop(Looper.java:137)
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.app.ActivityThread.main(ActivityThread.java:5041)
01-31 23:16:46.684: E/AndroidRuntime(831):  at java.lang.reflect.Method.invokeNative(Native Method)
01-31 23:16:46.684: E/AndroidRuntime(831):  at java.lang.reflect.Method.invoke(Method.java:511)
01-31 23:16:46.684: E/AndroidRuntime(831):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-31 23:16:46.684: E/AndroidRuntime(831):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-31 23:16:46.684: E/AndroidRuntime(831):  at dalvik.system.NativeStart.main(Native Method)
01-31 23:16:46.684: E/AndroidRuntime(831): Caused by: java.lang.NullPointerException
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.app.LoadedApk.initializeJavaContextClassLoader(LoadedApk.java:379)
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.app.LoadedApk.getClassLoader(LoadedApk.java:322)
01-31 23:16:46.684: E/AndroidRuntime(831):  at android.app.LoadedApk.makeApplication(LoadedApk.java:496)

Answer 1

错误发生在您的结果活动中。在onCreate方法中你有

...
// TODO Auto-generated method stub
setContentView(R.layout.resultado);
super.onCreate(savedInstanceState);
setupVariables(); 
...

您需要将呼叫转移到super.onCreate(savedInstanceState);到方法的开头。当处理android生命周期中的重写方法时，一些方法将首先调用super方法，而最后调用其他方法。他们中的任何人都不会在两者之间被召唤。检查开发人员文档以确定将来何时调用超级用户。

Answer 2

在Resultado中，您需要先致电super.onCreate(savedInstanceState) ，然后致电setContentView()。

应用程序崩溃从一个活动传递到另一个活动

2 个答案: