27. We read action from Intent

Lecture

In this lesson:

- we read action from Intent

In the last lesson, we made an illustrative example showing how action , Intent and Intent Filter are interrelated. In this lesson we will continue the topic. There are two news: good and good)

The first news. Intent Filter can contain several action . Thus, the Activity makes it clear that it is capable of several actions . For example, not only viewing pictures, but also editing. It turns out that the Activity can come up with different Intent with different actions.

The second news. An activity that was invoked using an Intent has access to this Intent and can read its attributes . Those. can find out what action was used.

We will do the following: create an Activity and set the Intent Filter to action = ru.startandroid.intent.action.showtime and action = ru.startandroid.intent.action.showdate . Thus, we denote that this Activity is capable of showing time and date. Next we will create an Intent either with action = ru.startandroid.intent.action.showtime , or with ru.startandroid.intent.action.showdate . Both of them will cause one Activity . And so that the Activity knows to show him the date or time, we will read the action from Intent and determine from it.

In general, now we start doing and everything will become clear)

Create a project:

Project name : P0271_GetIntentAction
Build Target : Android 2.3.3
Application name : GetIntentAction
Package name : ru.startandroid.develop.p0271getintentaction
Create Activity : MainActivity

Open main.xml and draw two buttons:

  <? xml version = "1.0" encoding = "utf-8"?> 
  <LinearLayout 
  xmlns: android = "http://schemas.android.com/apk/res/android" 
  android: layout_width = "fill_parent" 
  android: layout_height = "fill_parent" 
  android: orientation = "horizontal"> 
  <Button 
  android: layout_width = "wrap_content" 
  android: layout_height = "wrap_content" 
  android: id = "@ + id / btnTime" 
  android: text = "Show time"> 
  </ Button> 
  <Button 
  android: layout_width = "wrap_content" 
  android: layout_height = "wrap_content" 
  android: id = "@ + id / btnDate" 
  android: text = "Show date"> 
  </ Button> 
  </ LinearLayout>

The screen is exactly the same as in the previous lesson.

Code for MainActivity.java :

package ru.startandroid.develop.p0271getintentaction; 
 import android.app.Activity; 
 import android.content.Intent; 
 import android.os.Bundle; 
 import android.view.View; 
 import android.view.View.OnClickListener; 
 import android.widget.Button; 
 
 public class MainActivity extends Activity implements OnClickListener { 
 
 /** Called when the activity is first created. */ 
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.main); 
 
 Button btnTime = (Button) findViewById(R.id.btnTime); 
 Button btnDate = (Button) findViewById(R.id.btnDate); 
 
 btnTime.setOnClickListener(this); 
 btnDate.setOnClickListener(this); 
 } 
 
 @Override 
 public void onClick(View v) { 
 Intent intent; 
 
 switch(v.getId()) { 
 case R.id.btnTime: 
 intent = new Intent("ru.startandroid.intent.action.showtime"); 
 startActivity(intent); 
 break; 
 case R.id.btnDate: 
 intent = new Intent("ru.startandroid.intent.action.showdate"); 
 startActivity(intent); 
 break; 
 } 
 } 
 }

The code is also completely from the last lesson. We define the buttons, assign the handler - Activity , and call Intent by pressing. Now we will make an Activity that will catch both of these Intent.

First, create an info.xml layout file:

  <? xml version = "1.0" encoding = "utf-8"?> 
  <LinearLayout 
  xmlns: android = "http://schemas.android.com/apk/res/android" 
  android: layout_width = "match_parent" 
  android: layout_height = "match_parent" 
  android: orientation = "vertical"> 
  <Textview 
  android: layout_width = "wrap_content" 
  android: layout_height = "wrap_content" 
  android: id = "@ + id / tvInfo" 
  android: text = "TextView" 
  android: layout_gravity = "center_horizontal" 
  android: layout_marginTop = "20dp" 
  android: textSize = "30sp"> 
  </ TextView> 
  </ LinearLayout>

On the screen we have one TextView.

We create Activity , we will call it simply Info .

Info.java code:

package ru.startandroid.develop.p0271getintentaction; 
 
 import java.sql.Date; 
 import java.text.SimpleDateFormat; 
 
 import android.app.Activity; 
 import android.content.Intent; 
 import android.os.Bundle; 
 import android.widget.TextView; 
 
 public class Info extends Activity { 
 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.info); 
 
 // получаем Intent, который вызывал это Activity 
 Intent intent = getIntent(); 
 // читаем из него action 
 String action = intent.getAction(); 
 
 String format = "", textInfo = ""; 
 
 // в зависимости от action заполняем переменные 
 if (action.equals("ru.startandroid.intent.action.showtime")) { 
 format = "HH:mm:ss"; 
 textInfo = "Time: "; 
 } 
 else if (action.equals("ru.startandroid.intent.action.showdate")) { 
 format = "dd.MM.yyyy"; 
 textInfo = "Date: "; 
 } 
 
 // в зависимости от содержимого переменной format 
 // получаем дату или время в переменную datetime 
 SimpleDateFormat sdf = new SimpleDateFormat(format); 
 String datetime = sdf.format(new Date(System.currentTimeMillis())); 
 
 TextView tvDate = (TextView) findViewById(R.id.tvInfo); 
 tvDate.setText(textInfo + datetime); 
 } 
 }

We get the Intent using the getIntent () method, read the action from it and, depending on the value, create and display text.

Do not forget to register a new Activity in the manifest and create an Intent Filter for it with two action and category . And label specify Date / time info.