java - Android 新手，我的简单取名应用程序崩溃了

Question

大家好，我在学习 Android 时正在编写一个 name getter 应用程序，当它加载到模拟器中时，我被迫关闭该应用程序。我很新，所以这可能很简单。

namegetter.java

package edu.calpoly.android.lab1;
// tools
import android.app.Activity;
import android.content.Intent;
import android.content.pm.LabeledIntent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class NameGetter extends Activity implements android.view.View.OnClickListener{
    // variables
    private android.widget.EditText textEdit_Name;
    private android.widget.Button button_Submit;
    private String string_Name;
    private android.content.Intent intent_GetText;
    private android.os.Bundle bundle;
    private android.widget.TextView textView_Top;
    @Override
      public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.name_getter);

        // assign local variables
        textEdit_Name = (EditText) this.findViewById(R.id.editText_Name);
        button_Submit = (Button) this.findViewById(R.id.button_Submit);
        textView_Top = (TextView) this.findViewById(R.id.LABEL1);
        button_Submit.setOnClickListener(this);

       bundle = this.getIntent().getExtras();

       bundle.getString(string_Name);
       textView_Top.setText(string_Name);


    }

    public void onClick(View v) {
        string_Name = textEdit_Name.getText().toString();
        // create intent to pass
        intent_GetText= new Intent(this, HelloWorld.class);
        // pass to hello world activity
        intent_GetText.putExtra(string_Name, textEdit_Name.getText().toString());
        // initiate 
        this.startActivity(intent_GetText);
    }
}

list .xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="edu.calpoly.android.lab1"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="12" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name="NameGetter"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name="HelloWorld" ></activity>

    </application>
</manifest>

Answer 1

最可能的原因是 getExtras() 返回 null。

bundle = this.getIntent().getExtras();
bundle.getString(string_Name);

如需更多帮助，我建议收集 logcat (adb logcat) 并发布实际异常。