talks/2016/02/android.slide

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Android
February 25, 2016
Brian Buller
Buller Codeworks, LLC
* Generally
Native Android is Java...
* Generally
Native Android is Java...
but I'm not talking about that
* Android Manifest
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.application"
android:versionCode="3"
android:versionName="1.2" >
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application android:label="@string/app_name"
android:icon="@drawable/ic_launcher"
android:theme="@android:style/Theme.Holo.Light" >
<activity android:name=".FeedListActivity"
android:label="@string/app_name"
android:launchMode="singleInstance">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
...
</application>
</manifest>
* Permissions
- Sandboxed Applications
- Normal Permissions
The permission must be declared, but the system automatically grants access
- Dangerous Permissions
The user must grant permission
- Changes in Android 6
- List of permissions and severity at [[http://developer.android.com/guide/topics/security/permissions.html]]
* Permissions Example
- Declared in manifest
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
- Request at run time
ActivityCompat.requestPermissions(thisActivity,
new String[]{Manifest.permission.READ_CONTACTS},
MY_PERMISSIONS_REQUEST_READ_CONTACTS);
* Intents
- Declare in manifest
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
- Call in code
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND);
shareIntent.putExtra(Intent.EXTRA_TEXT, alert_message);
shareIntent.setType("text/plain");
startActivity(shareIntent);
* Activities
Main Activity (icon in launcher)
<activity android:name=".FeedListActivity"
android:label="@string/app_name"
android:launchMode="singleInstance">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
Other Activities
<activity android:name=".FeedDetailActivity"
android:label="@string/app_name"
android:launchMode="singleInstance">
</activity>
* Application Lifecycle
General Lifecycle
- Resumed
The activity has the user focus (aka - Running)
- Paused
Another activity is in the foreground, but this one is still visisble.
A Paused activity is fully alive but can be killed by the system in extremely
low-memory situations.
- Stopped
The activity is completely obscured by another activity. The activity is still alive,
but no longer visible and can be killed if memory is needed elsewhere.
* Application Lifecycle
Functions
- onCreate - The activity is being created
- onStart - The activity is about to become visible
- onResume - The activity has become visible
- onPause - Another activity is taking focus
- onStop - The activity is no longer visible
- onDestroy - The activity is about to be destroyed
Those are all overrides and you *must* hit the overridden function before doing any work in them.
* Layout Files
<LinearLayout
android:id="@+id/layout_id"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView android:id="@+id/layout_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Text"
android:textSize="25dip" />
<Button android:id="@+id/layout_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button Text" />
<LinearLayout android:id="@+id/list_wrapper"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView android:id="@+id/list_view"
android:listSelector="#00000000"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</LinearLayout>
* Notes
The slides are available on [[http://gogs.bullercodeworks.com/brian/talks/2016/02/android.slide]]