我创建了一个包含两个活动的Android应用程序，但无法从第二个活动切换回第一个

Question

我创建了一个包含两个活动的Android应用程序，但第二个活动的按钮似乎无法正常工作。第一个活动的按钮（一个地图活动和一个添加信息的按钮，用户通过信息输入屏幕接受第二个活动）工作正常，第二个活动的按钮似乎都没有任何影响......我不能甚至可以使OnClick Toast消息发挥作用。

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback , LocationListener { 

    public void AddMapInfo(View view) { 

    Intent intent = new Intent(this, InformationInputActivity.class); 
    LatLng providedLocation = current; 
    Bundle args = new Bundle(); 
    args.putParcelable("provided_location", providedLocation); 
    intent.putExtra("bundle", args); 
    startActivityForResult(intent, 1); 
} 

public void onActivityResult (int requestCode, int resultCode, Intent data){ 
    Toast.makeText(this, "back with cheese!", Toast.LENGTH_LONG).show(); 

    if (requestCode != 1){ 

     Toast.makeText(this, "Oops... This shouldn't happen", Toast.LENGTH_LONG).show(); 

    } 
    else{ 

     setContentView(R.layout.activity_maps); 
     InformationPoint informationPoint = (InformationPoint) data.getSerializableExtra("information_point"); 

     informationPoint.display(mymap); 

    } 

} 


} 

第二个活动带来的布局屏幕，并将其设置为的EditText字段的正确选择，所以我知道它得到控制......但仅此而已。没有来自任何方法的Toast消息（当第一个活动接收到位置更新信息时，我仍然得到Toasts），单选按钮或提交按钮似乎都不起作用，我也没有得到结果并控制第一次活动。 （之前，我曾经能够在单选按钮上的选项上得到Toast，但现在看起来也不起作用）。尝试发送活动结果会中止应用程序（因为我将finish（）添加到第二个活动中）。

/* java */ 
package com.example.m.googlemapappfirst; 

import android.content.Intent; 
import android.support.v7.app.ActionBarActivity; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.RadioButton; 
import android.widget.TextView; 
import android.widget.Toast; 

import com.google.android.gms.maps.model.LatLng; 

import org.w3c.dom.Text; 


public class InformationInputActivity extends ActionBarActivity { 

EditText editText; 
String content = ""; 
LatLng providedLocation; 

public InfoType infoType = InfoType.NO_INFO; 
InformationPoint informationPoint; 

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

    Intent intent = getIntent(); 
    Bundle bundle = getIntent().getParcelableExtra("bundle"); 
    providedLocation = bundle.getParcelable("provided_location"); 
    String message = String.valueOf(providedLocation); 

    editText = (EditText)findViewById(R.id.description); 
    editText.setHorizontallyScrolling(false); 
    editText.setMaxLines(5); 


    Toast.makeText(this, "enter cheese info", Toast.LENGTH_LONG); 

} 

public void onRadioButtonClicked(View view) { 
    // Is the button now checked? 


    boolean checked = ((RadioButton) view).isChecked(); 


    Toast.makeText(this,"you selected your cheese", Toast.LENGTH_LONG); 


} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.menu_information_input, menu); 
    return true; 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    // Handle action bar item clicks here. The action bar will 
    // automatically handle clicks on the Home/Up button, so long 
    // as you specify a parent activity in AndroidManifest.xml. 
    int id = item.getItemId(); 

    //noinspection SimplifiableIfStatement 
    if (id == R.id.action_settings) { 
     return true; 
    } 

    return super.onOptionsItemSelected(item); 
} 


public void AddPictureHandler(View view){ 
    Toast.makeText(this, "i like to take pictures of cheese", Toast.LENGTH_LONG).show(); 
} 

public void SubmitHandler(View view){ 
    content = editText.getText().toString(); 

    Toast.makeText(this, "add cheese info", Toast.LENGTH_LONG).show(); 

    if(infoType == InfoType.NO_INFO){ 

     Toast.makeText(this, "Please select an Information type", Toast.LENGTH_LONG).show(); 
    } 
    else if(content.equals("")){ 

     Toast.makeText(this, "Please write a description", Toast.LENGTH_LONG).show(); 

    } 

    informationPoint = new InformationPoint(providedLocation, infoType, content); 

    Intent returnIntent = new Intent(this, MapsActivity.class); 
    returnIntent.putExtra("information_point", informationPoint); 

    this.setResult(1, returnIntent); 
    finish(); /* added after original post, this makes app crash consistently */ 


} 

} 

这里的第二个活动的XML布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" 
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" 
android:paddingRight="@dimen/activity_horizontal_margin" 
android:paddingTop="@dimen/activity_vertical_margin" 
android:paddingBottom="@dimen/activity_vertical_margin" 
android:orientation="vertical" 
tools:context="com.example.m.googlemapappfirst.InformationInputActivity"> 

<TextView android:text="@string/instructions" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" /> 

<RadioGroup xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:orientation="vertical"> 
    <RadioButton android:id="@+id/radio_swiss" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/swiss" 
     android:onClick="onRadioButtonClicked"/> 
    <RadioButton android:id="@+id/radio_american" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/american" 
     android:onClick="onRadioButtonClicked"/> 
    <RadioButton android:id="@+id/radio_gruyere" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/gruyere" 
     android:onClick="onRadioButtonClicked"/> 
    <RadioButton android:id="@+id/radio_cheddar" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/cheddar" 
     android:onClick="onRadioButtonClicked"/> 
</RadioGroup> 

<TextView android:text="@string/instructions2" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" /> 


<EditText 
    android:id="@+id/description" 
    android:layout_width="fill_parent" 
    android:layout_height="60dp" 
    android:layout_weight="1" 
    android:hint="@string/type_here" 
    android:inputType="text" 
    android:imeOptions="actionDone" 
    android:maxLines ="4" 
    android:maxLength ="2000" 
    android:scrollHorizontally="false" 
    /> 


<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:orientation="horizontal"> 


    <Button 
     android:id="@+id/take_picture_button" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Add Picture" 
     android:onClick="AddPictureHandler" /> 

    <Button 
     android:id="@+id/submit_button" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="Report Information" 
     android:onClick="SubmitHandler" /> 

</LinearLayout> 

Answer 1

我没有看到土司创建之后的任何问题，但节目的缺失调用（），就像这样：

Toast.makeText(this, "Oops... This shouldn't happen", Toast.LENGTH_LONG).show();