我正在制作我的第一个Android应用程序。我正在尝试从另一个名为SendMessage
的活动中启动名为AskReport
的活动。我在SO上看到了类似这样的问题,但没有一个我能找到匹配的问题。
AskReport
活动的代码如下:
public class AskReport extends Activity
{
Button done;
RadioButton checkedRadioButton;
RadioGroup group;
EditText email, info;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.ask_report);
done = (Button) findViewById(R.id.Report);
group = (RadioGroup) findViewById(R.id.radioGroup1);
checkedRadioButton = (RadioButton) findViewById(group.getCheckedRadioButtonId());
info = (EditText) findViewById(R.id.Info);
email = (EditText) findViewById(R.id.Email);
}
public void reportClick(View view){
Intent intent = new Intent(this, SendMessage.class);
/* Line1 */ intent.putExtra("sender_email", email.getText());
/* Line2 */ intent.putExtra("additional_info", info.getText());
/* Line3 */ intent.putExtra("checked_button",checkedRadioButton.getText());
startActivity(intent);
}
}
活动SendMessage
的代码如下:
public class SendMessage extends Activity
{
String message = "";
EditText message_to_send;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.send_message);
message_to_send = (EditText) findViewById(R.id.message_to_send);
Intent intent = getIntent();
message += intent.getStringExtra("sender_email");
message += intent.getStringExtra("additional_info");
message += intent.getStringExtra("checked_button");
message_to_send.setText(message);
}
}
在我注释掉AskReport
活动中标记的三行后,SendMessage
活动被成功调用,但显示的文字为nullnullnull
(可理解)。
我已在清单中正确标记了活动条目。
另外,我还在这里给出了出现的logcat消息:
09-10 15:12:57.555: E/AndroidRuntime(1311): FATAL EXCEPTION: main
09-10 15:12:57.555: E/AndroidRuntime(1311): java.lang.IllegalStateException: Could not execute method of the activity
09-10 15:12:57.555: E/AndroidRuntime(1311): at android.view.View$1.onClick(View.java:3591)
09-10 15:12:57.555: E/AndroidRuntime(1311): at android.view.View.performClick(View.java:4084)
09-10 15:12:57.555: E/AndroidRuntime(1311): at android.view.View$PerformClick.run(View.java:16966)
09-10 15:12:57.555: E/AndroidRuntime(1311): at android.os.Handler.handleCallback(Handler.java:615)
09-10 15:12:57.555: E/AndroidRuntime(1311): at android.os.Handler.dispatchMessage(Handler.java:92)
09-10 15:12:57.555: E/AndroidRuntime(1311): at android.os.Looper.loop(Looper.java:137)
09-10 15:12:57.555: E/AndroidRuntime(1311): at android.app.ActivityThread.main(ActivityThread.java:4745)
09-10 15:12:57.555: E/AndroidRuntime(1311): at java.lang.reflect.Method.invokeNative(Native Method)
09-10 15:12:57.555: E/AndroidRuntime(1311): at java.lang.reflect.Method.invoke(Method.java:511)
09-10 15:12:57.555: E/AndroidRuntime(1311): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-10 15:12:57.555: E/AndroidRuntime(1311): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-10 15:12:57.555: E/AndroidRuntime(1311): at dalvik.system.NativeStart.main(Native Method)
09-10 15:12:57.555: E/AndroidRuntime(1311): Caused by: java.lang.reflect.InvocationTargetException
09-10 15:12:57.555: E/AndroidRuntime(1311): at java.lang.reflect.Method.invokeNative(Native Method)
09-10 15:12:57.555: E/AndroidRuntime(1311): at java.lang.reflect.Method.invoke(Method.java:511)
09-10 15:12:57.555: E/AndroidRuntime(1311): at android.view.View$1.onClick(View.java:3586)
09-10 15:12:57.555: E/AndroidRuntime(1311): ... 11 more
09-10 15:12:57.555: E/AndroidRuntime(1311): Caused by: java.lang.NullPointerException
09-10 15:12:57.555: E/AndroidRuntime(1311): at com.example.safeworld.AskReport.reportClick(AskReport.java:44)
09-10 15:12:57.555: E/AndroidRuntime(1311): ... 14 more
09-10 15:13:00.725: I/Process(1311): Sending signal. PID: 1311 SIG: 9
我还将函数放在android:onClick="XXXXXX"
中的相应layout.xml中。
请帮我弄清楚这三行出了什么问题。谢谢你的帮助!
编辑:
这是我的ask_report.xml
:
<?xml version="1.0" encoding="UTF-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/TableLayout2"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<TextView
android:id="@+id/ask"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/ask_report"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="24dp" />
<RadioGroup
android:id="@+id/radioGroup1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<RadioButton
android:id="@+id/road_accident"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="12dp"
android:text="@string/road_accident" />
<RadioButton
android:id="@+id/fire"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="12dp"
android:text="@string/fire" />
<RadioButton
android:id="@+id/theft"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="12dp"
android:text="@string/theft" />
<RadioButton
android:id="@+id/other"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="12dp"
android:layout_marginBottom="12dp"
android:text="@string/other" />
</RadioGroup>
<TextView
android:id="@+id/AddInfo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/add_detail" />
<EditText
android:id="@+id/Info"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="text" >
</EditText>
<TextView
android:id="@+id/AskEmail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/enter_email"
android:layout_marginTop="10dp" />
<EditText
android:id="@+id/Email"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textEmailAddress" />
<Button
android:id="@+id/Report"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/done"
android:onClick="reportClick" />
</TableLayout>
答案 0 :(得分:1)
从堆栈跟踪判断我会说其中一行返回null
:
checkedRadioButton = (RadioButton) findViewById(group.getCheckedRadioButtonId());
info = (EditText) findViewById(R.id.Info);
email = (EditText) findViewById(R.id.Email);
打印所有三个视图的值,如果其中一个为空,则检查ID是否正确并且它们位于布局ask_report
答案 1 :(得分:1)
也许是因为你从EditText
得到了文字,就像下面这样 -
intent.putExtra("sender_email", email.getText().toString());
intent.putExtra("additional_info", info.getText().toString());
intent.putExtra("checked_button",checkedRadioButton.getText().toString());
您忘记使用.toString()
从EditText
<强>更新强>
好的,最好通过radioButton
RadioGroup
Button
onClick
方法中的// Gets a reference to our radio group
// rBtnDigits is the name of our radio group (code not shown)
RadioGroup g = (RadioGroup) findViewById(R.id.radioGroup1);
// Returns an integer which represents the selected radio button's ID
int selected = g.getCheckedRadioButtonId();
// Gets a reference to our "selected" radio button
RadioButton b = (RadioButton) findViewById(selected);
intent.putExtra("sender_email", email.getText().toString());
intent.putExtra("additional_info", info.getText().toString());
// Now you can get the text or whatever you want from the "selected" radio button
intent.putExtra("checked_button",b.getText());
来获取文字。
{{1}}
答案 2 :(得分:0)
Android在您定义
时只为您实现OnClickListenerandroid:onClick="someMethod"
答案 3 :(得分:0)
嗯,我想我会自己回答这个问题,并让所有读过这篇文章的人知道答案。
三条标记线的问题位于Line3
,因为null
中的checkedRadioButton
值为android:checkedButton="@+id/road_accident"
。
有效的是:
RadioGroup
添加了RoadAccident
,默认选择onCheckedChangedListener
。RadioGroup
添加到成功提供checkedRadioButton
的{{1}}。代码如下:
group = (RadioGroup) findViewById(R.id.radioGroup1);
group.setOnCheckedChangeListener(new OnCheckedChangeListener(){
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
// TODO Auto-generated method stub
checkedRadioButton = (RadioButton) group.findViewById(checkedId);
}
});
checkedRadioButton = (RadioButton) group.findViewById(group.getCheckedRadioButtonId());
现在Line3可以正常运行。
<强>现金:强> 感谢@marmor和@SpK的帮助。抱歉,无法选择你的答案之一,因为我从你们两个人那里拿了一半。