调用另一个Activity 分类: H1_ANDROID 2013-09-22 14:11 2217人阅读 评论(0) 收藏
参考自Google官方文档Traning/Getting Started/Building a simple user interface, Startinganother activity,http://developer.android.com/training/basics/firstapp/building-ui.html
1、创建主Activity
使用Eclipse新建项目MyFirstApp,UI布局如下:
<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" android:orientation="horizontal" tools:context=".MainActivity"> <EditText android:id="@+id/et_message" android:layout_height="wrap_content" android:layout_width="0dp" android:layout_weight="1" android:hint="@string/input_here"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/click" android:onClick="sendMessage"/> </LinearLayout>
注意通过权重来分配尺寸的方式
组件1:
android:layout_width="0dp" android:layout_weight="1"
组件2:
android:layout_width="wrap_content"
2、在主类中指定onclick所对应的sendMessage方法
package com.lujinhong.androidtraningmyfirstapp; 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.lujinhong.myfirstapp.MESSAGE"; @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override public boolean onCreateOptionsMenu(Menu menu){ // Inflate themenu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } public void sendMessage(View v){ EditText et_message=(EditText)this.findViewById(R.id.et_message); String message= et_message.getText().toString().trim(); Intent intent= new Intent(this,DisplayMessageActivity.class); intent.putExtra(EXTRA_MESSAGE, message); this.startActivity(intent); } }
(1)关于intent
An Intent isan object that provides runtime binding between separate components (such astwo activities). TheIntent representsan app’s "intent to do something." You can use intents for a widevariety of tasks, but most often they’re used to startanother activity.
(2)调用另一个activity的步骤:
l 首先取得editText中的文字
EditText et_message = (EditText) this.findViewById(R.id.et_message); String message = et_message.getText().toString().trim();
l 然后创建一下intent,并把文字作为K-V形式保存到intent中
Intent intent= new Intent(this,DisplayMessageActivity.class); intent.putExtra(EXTRA_MESSAGE, message);
创建intent时,通过一个类名,指定调用哪个类文件。
l 最后启动一个新的activity.
this.startActivity(intent);
3、显示另一个Activity
package com.lujinhong.androidtraningmyfirstapp; import android.os.Bundle; import android.app.Activity; import android.content.Intent; import android.view.Menu; import android.widget.TextView; public class DisplayMessageActivityextends Activity{ @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_display_message); // Get the messagefrom the intent Intent intent= getIntent(); String message= intent.getStringExtra(MainActivity.EXTRA_MESSAGE); // Create the textview TextView textView=new TextView(this); textView.setTextSize(40); textView.setText(message); // Set the textview as the activity layout setContentView(textView); } @Override public boolean onCreateOptionsMenu(Menu menu){ // Inflate themenu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.display_message, menu); return true; } }
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