我正在使用输入事件应用。该应用程序有一个文本字段和一个按钮。输入的信息将发送到接收器应用程序，在那里它处理操作，然后我们必须能够写入主活动中的文本视图。希望这个解释不会太混乱。
这是我构建主应用程序的地方：http://developer.android.com/guide/topics/ui/ui-events.html
这是我构建接收器的地方： http://developer.android.com/training/sharing/receive.html
主要应用加载但布局为空白。接收器在负载时崩溃。我无法确切知道原因，因此非常感谢一些帮助。
MainActivity.java（主应用）
package com.miller.main;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
protected void onCreate(Bundle savedInstanceState, Bundle savedValues) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Capture our button from layout
final Button button = (Button)findViewById(R.id.corky);
OnClickListener mCorkyListener = null;
// Register the onClick listener with the implementation above
button.setOnClickListener(mCorkyListener);
// Create an anonymous implementation of OnClickListener
@SuppressWarnings("unused") OnClickListener mCorkyListener1 = new OnClickListener() {
@SuppressWarnings("null")
public void onClick(View v) {
// do something when the button is clicked
// Capture our button from layout
button.setOnClickListener(this);
Intent sendIntent = new Intent();
sendIntent.setAction(Intent.ACTION_SEND);
sendIntent.putExtra(Intent.EXTRA_TEXT, "This is my text to send.");
sendIntent.setType("text/plain");
PackageManager packageManager = getPackageManager();
Intent intent = null;
List<ResolveInfo> activities = packageManager.queryIntentActivities(intent, 0);
boolean isIntentSafe = activities.size() > 0;
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(sendIntent);
}
};
}
@Override
protected void onPause() {
Log.w("Monday", "Paused");
super.onPause();
Log.w("Monday", "Paused");
// Another activity is taking focus (this activity is about to be "paused").
}
@Override
protected void onStop() {
Log.w("Tuesday", "Stopped");
super.onStop();
Log.w("Tuesday", "Stopped");
// The activity is no longer visible (it is now "stopped")
}
}
activity_main.xml（主应用）
<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.miller.main.MainActivity" >
<EditText
android:id="@+id/text_field"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="@string/text_field"
android:inputType="text" />
<Button
android:id="@+id/corky"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button_text"
android:layout_below="@+id/text_field" />
</RelativeLayout>
MainActivity.java（接收方应用）
package com.miller.receiver;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
// Get intent, action and MIME type
Intent intent = getIntent();
String action = intent.getAction();
String type = intent.getType(); {
if (Intent.ACTION_SEND.equals(action) && type != null) {
if ("text/plain".equals(type)) {
handleSendText(intent); // Handle text being sent
} else if (type.startsWith("image/")) {
handleSendImage(intent); // Handle single image being sent
}
} else if (Intent.ACTION_SEND_MULTIPLE.equals(action) && type != null) {
if (type.startsWith("image/")) {
handleSendMultipleImages(intent); // Handle multiple images being sent
}
} else {
// Handle other intents, such as being started from the home screen
}
}
void handleSendText(Intent intent) {
String sharedText = intent.getStringExtra(Intent.EXTRA_TEXT);
if (sharedText != null) {
// Update UI to reflect text being shared
}
}
void handleSendImage(Intent intent) {
Uri imageUri = (Uri) intent.getParcelableExtra(Intent.EXTRA_STREAM);
if (imageUri != null) {
// Update UI to reflect image being shared
}
}
void handleSendMultipleImages(Intent intent) {
ArrayList<Uri> imageUris = intent.getParcelableArrayListExtra(Intent.EXTRA_STREAM);
if (imageUris != null) {
// Update UI to reflect multiple images being shared
}
}
}
activity_main.xml目前只是默认值。
Logcat for Receiver app
04-09 15:41:11.244: E/AndroidRuntime(1114): FATAL EXCEPTION: main
04-09 15:41:11.244: E/AndroidRuntime(1114): Process: com.miller.receiver, PID: 1114
04-09 15:41:11.244: E/AndroidRuntime(1114): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.miller.receiver/com.miller.receiver.MainActivity}: java.lang.NullPointerException
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.app.ActivityThread.access$800(ActivityThread.java:135)
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.os.Handler.dispatchMessage(Handler.java:102)
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.os.Looper.loop(Looper.java:136)
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.app.ActivityThread.main(ActivityThread.java:5017)
04-09 15:41:11.244: E/AndroidRuntime(1114): at java.lang.reflect.Method.invokeNative(Native Method)
04-09 15:41:11.244: E/AndroidRuntime(1114): at java.lang.reflect.Method.invoke(Method.java:515)
04-09 15:41:11.244: E/AndroidRuntime(1114): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-09 15:41:11.244: E/AndroidRuntime(1114): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-09 15:41:11.244: E/AndroidRuntime(1114): at dalvik.system.NativeStart.main(Native Method)
04-09 15:41:11.244: E/AndroidRuntime(1114): Caused by: java.lang.NullPointerException
04-09 15:41:11.244: E/AndroidRuntime(1114): at com.miller.receiver.MainActivity.<init>(MainActivity.java:20)
04-09 15:41:11.244: E/AndroidRuntime(1114): at java.lang.Class.newInstanceImpl(Native Method)
04-09 15:41:11.244: E/AndroidRuntime(1114): at java.lang.Class.newInstance(Class.java:1208)
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
04-09 15:41:11.244: E/AndroidRuntime(1114): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
04-09 15:41:11.244: E/AndroidRuntime(1114): ... 11 more