当我创建我的MyFirstApp项目(顺便提一下我命名为SampleNotes)时,我使用CyanogenMod 10.1 Nook HD +运行它,使用内置ADB over wifi,我尝试点击发送按钮,它只是没有什么都不做;就好像我从未添加任何有关意图或第二项活动的内容。有人可以帮忙吗?
MainActivity.java:
package com.example.samplenotes;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.SampleNotes.MESSAGE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
/** Called when the user clicks the Send button */
public void sendMessage(View view) {
//Do something in response to button
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
}
}
的AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.samplenotes"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.samplenotes.MainActivity"
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="com.example.samplenotes.DisplayMessageActivity"
android:label="@string/title_activity_display_message"
android:parentActivityName="com.example.SampleNotes.MainActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.example.SampleNotes.MainActivity" />
</activity>
</application>
</manifest>
DisplayMessageActivity.java:
package com.example.samplenotes;
import android.os.Bundle;
import android.app.Activity;
import android.view.MenuItem;
import android.widget.TextView;
import android.support.v4.app.NavUtils;
import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Build;
public class DisplayMessageActivity extends Activity {
@SuppressLint("NewApi")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Get message from intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
setContentView(R.layout.activity_display_message);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
getActionBar().setDisplayHomeAsUpEnabled(true);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
}
activity_main.xml中:
<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: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=".MainActivity"
android:orientation="horizontal" >
<EditText android:id="@+id/edit_message"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:hint="@string/edit_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button_send"
android:onClick="sendMessage" />
</LinearLayout>
activity_display_message.xml:
<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=".DisplayMessageActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
</RelativeLayout>
的strings.xml:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">SampleNotes</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<string name="edit_message">Enter a message</string>
<string name="button_send">Send</string>
<string name="title_activity_display_message">My Message</string>
</resources>
答案 0 :(得分:1)
正如其他人所说,要开始活动,你需要致电:
startActivity();
此外,在您的DisplayMessageActivity中,在操作任何控件之前,必须先设置布局:
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//first, set main layout
setContentView(R.layout.activity_display_message);
然后获取文本视图并进行设置:
//Get message from intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
TextView textView = (TextView) findViewById(R.id.text);
textView.setTextSize(40);
textView.setText(message);
在activity_display_message.xml中添加id,以便检索textView:
<TextView
android:oid="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
答案 1 :(得分:0)
您实际上并未在发送功能中启动活动:
//Do something in response to button Intent intent = new Intent(this, DisplayMessageActivity.class); EditText editText = (EditText) findViewById(R.id.edit_message); String message = editText.getText().toString(); intent.putExtra(EXTRA_MESSAGE, message); //add this to start your activity startActivity(intent);
答案 2 :(得分:0)
在sendMessage函数的末尾添加此行:
startActivity(意向);
删除行setContentView .. 来自第二项活动的onCreate。