Minzhao Liu

android notes

Android Course Notes

Virtual Device

Telnet

telnet localhost 80
sms send 111 hello
power capacity 0
help window
window scale 0.5
avd stop

New: 1507 Ram, 100 MB

Resourse

Under res/layout , and res/values.

Syntax

> = >
&lt; = <
&amp;

Logcat

import android.util.Log
Log.e('tag', 'msg')

Put them in main activity.xml

ImageView

Put images in a new folder media, then copy needed to res/drawable-mdpi, then under activity_main.xml, grab Palette/ImageView to the main.

In xml file:

<ImageView ...
android:contentDescription = ""

Properties:

scaleType = 'fitXY'
adjustViewBounds = 'true'

TextView

Properties:

paddingLeft = '16dp'
textSize = '16sp'
paddingTop = '8dp'

ID

@+id/jkj: create
@id/ : cite

R.java

Files

activity_main.xml
strings.xml

MainActivity.java

Layout-land (layout-landscape)

make new folder layout-land under res, and copy activity_main.xml in it.

ScrollView

layout_width = "match_parent"
layout_height = "match_parent"
layout_below = "@id/imageView1"

wrap TextView

ScrollView + LinearLayout

<ScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@id/hearthstone"
    android:layout_margin="8dp"
    android:scrollbars="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >

        <ImageView
            android:id="@+id/chicken"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:adjustViewBounds="true"
            android:layout_margin="8dp"
            android:src="@drawable/chicken" />

HorizontalScroll + LinearLayout

   <HorizontalScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="8dp"
     >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal" >

Export

manifest -> export wizard.

Make new folder as publish

Format

cmd + a
cmd + shift + f

MediaPlayer

  • Resources put in the folder res/raw

  • Modify Main...java:

    onCreate: MediaPlayer mp = MediaPlayer.create(this, R.raw.ex…); mp.start();

Life Cycle

OnCreate()
OnResume()
OnPause()

Also need to define MediaPlayer mp under MainActivity before OnPause.

Button

  • add (drag)

  • change property: on click (yourmethod)

      android:onClick="wiki"

  • edit java file, under (yourmethod)

      public void wiki(View v){
  String url = "http://en.wikipedia.org/wiki/Jabberwocky";
  Intent i = new Intent(Intent.ACTION_VIEW);
  i.setData(Uri.parse(url));
  startActivity(i);
  }

Debug

Log.e("pickle", "onCreate")
Import Log;

set Breakpoint. Debug as.

Diagram

onPause -> mp.stop();, mp.release()

Manifest

Under Manifest:

config changes = "orientation|screenSize|uimode"

or

android:screenOrientation = "portrait"

to avoid start background music again

Style

under values/styles.xml.

<style name = "mystyle" parent = "@android:style/TextAppearanceLarge"
<item> ...

Usage

style = "@style/mystyle"

Enable external android device to debug

about phone -> build number 7 times -> usb debug enable

Webview

drag a WebView under Composite. Copy html file etc under asset folder

android:id="@+id/webView1"
android:layout_width="match_parent"
android:layout_height="match_parent"/>

Modify your onCreate method to include the following two lines:

WebView myWebView = (WebView) findViewById(R.id.webView1);
myWebView.loadUrl("file:///android_asset/index.html");

Enable zoom controls

myWebView.getSettings().setBuiltInZoomControls(true);
myWebView.getSettings().setJavaScriptEnabled(true);
mywebview.getSettings().setDomStorageEnabled(true);

Add new activity that is accessible from the Launcher, create a 3rd activity :

Intent intent = new Intent();
intent.setClass(this, YourFirstActivity.class);
if (Math.random() > 0.5) {
// Open the Java Book instead!
intent.setClass(this, YourSecondActivity.class);
}
startActivity(intent);
finish();

Permission

AndroidManifest.xml -> Permission -> uses internet

New activity

file, new, others, android activity.

Remember title and check laucher.

 <activity
        android:name="com.****.webviewapp.NasaActivity"
        android:label="@string/title_activity_nasa" >
                    <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

Can just delete the layout file and use previous one.

Linear Layout

<LinearLayout
	android:orientation = "vertical">

vertical or horizontal

EditText

<EditText
	android:hint = "full name">
	<requestFocus />
</EditText>

request focus

android:minLines = "3"

inputType

<EditText
	android:inputType = "textPersonName">
	textEmailAddress
	phone
	textMultiLine

ImageButton

<ImageButton
	android:onClick = "processForm" />

and add to MainActivity.java:

public void processForm(View duck) {
	duck.setVisibility(View.INVISIBLE); // GONE ; make it disaapear
	Toast.makeText(this.getApplicationContext(), R.string.app_name, Toast.LENGTH_LONG).show;
	String email = mEmail.getText().toString();
		// .toLowerCase().contains("duck"); // contains gives T or F
	Toast.makeText(this.getApplicationContext(), email, Toast.LENGTH_LONG).show();
}

Toast : print message

can set android:layout_gravity = 'right';

and also

android:layout_weight = "10"
android:adjustViewBounds = "true" // to fill bounds

view name

In java code:

private EditText mName;

then in onCreate:

mName = (EditText) findViewByID(R.id.name);
mEmail = (EditText) findViewByID(R.id.email);

for general view

private View mName;

then in onCreate:

mName = findViewByID(R.id.name);

and it should be after setContentView

Play with String

int position email.indexOF("@");
if (position == -1){
	Toast....
	mEmail.requestFocus();  // request focus
	return;
}

String username = email.substring(0, position);
String thankyou = "Thankyou " + username;

if ( ! email.contains("@")){
}

int len = comments.length();

int value = Integer.parseInt(phone);

name.equals("Fere")

try

int value = -1;
boolean valueOK = false;
try {
	value = ...;
	valueOK = true;
} catch(Exception e){
	Log.d("fdsf", "fdjsfj");
}

animation

Animation anim = AnimationUtils.makeOutAnimation(this, true)
duck.startAnimation(anim);

Share

SEND

In public void processForm method:

Intent i = new Intent(Intent.ACTION_SEND);
i.setType("text/plain");
i.putExtra(Intent.EXTRA_TEXT, "Whata");
startActivity(i);

SMS message

Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse("sms:" + phone));
i.putExtra("sms_body", coments);
startActivity(i);

Email

Intent i = new Intent(Intent.ACTION_SENDTO, Uri.fromParts("mailto", "someone@somewhere", null));
i.putExtra(Intent.EXTRA_SUBJECT, "important");
i.putExtra(Intent.EXTRA_TEXT, message);
startActivity(i);

try{
startActivity(i);
} catch(Exception e) {
	Toast...
}

if (i.resolveActivity(getPackageManager()) = null) {
	Toast...
} else {
startActivity( Intent.createChooser(i, "choose email"));
}

ScrollView

Use scrollview to wrap linearlayout

Published

20 December 2013

Modified

2 February 2014

Tags