Android Intent and intent filters
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The document explains the concept of intents in Android development, differentiating between explicit and implicit intents used to start components and share data. It provides examples of how to create an implicit intent for sending text messages and how to receive intents using intent filters. Additionally, it discusses intent resolution criteria including action, data URI, and category.
Android Intent and intent filters
- 1. INTENT Google meaning - intention or purpose. StackOverFlow - a messaging object you can use to request an action from another app component
- 2. TYPES Explicit Intents - You will provide fully qualified name of component to start -Within your app 01 Implicit Intents – You will provide action to perform system starts the action. 02
- 3. INTENT USAGES • To start components. • To share data.
- 4. EXAMPLES Implicit Intent • // Create the text message with a string • Intent sendIntent = new Intent(); • sendIntent.setAction(Intent.ACTION_SEND); • sendIntent.putExtra(Intent.EXTRA_TEXT, textMessage); • sendIntent.setType("text/plain"); • //sendIntent.setType("text/plain"); • // Verify that the intent will resolve to an activity • if (sendIntent.resolveActivity(getPackageManager()) != null) { • startActivity(sendIntent); • } Explicit Intent • startActivity(new Intent(Mainactivity.this,SecondActivity.class));
- 5. HOW TO RECEIVE INTENTS • Using intent-filters. <intent-filter/> • To receive plain text : <intent-filter> <action android:name="android.intent.action.SEND" /> <category android:name="android.intent.category.DEFAULT" /> <data android:mimeType="text/plain" /> </intent-filter>
- 6. HANDLING INCOMING INTENTS onCreate (Bundle savedInstanceState) { ... // 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 } } }
- 7. INTENT RESOLUTION • Action. • Data (both URI and data type). • Category.