Basics of Android App development: new features

Fragment

• Purpose: Switch the interface in an activity, switch the interface only to switch the contents of fragment
• The life cycle approach is consistent with activity and can be understood as an activity

• Defining the layout file as a fragment display

  //此方法返回的View就会被显示在Fragment上@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,    Bundle savedInstanceState) {    // TODO Auto-generated method stub    //用布局文件填充成一个View对象，返回出去，那么就显示在Fragment上了    View v = inflater.inflate(R.layout.fragment01, null);    return v;     }

• Display the fragment to the specified ViewGroup

  //把fragment显示至界面//new出fragment对象Fragment01 fg = new Fragment01();FragmentManager fm = getFragmentManager();//开启事务FragmentTransaction ft = fm.beginTransaction();//把fragment对象显示到指定资源id的组件里面ft.replace(R.id.fl, fg);ft.commit();

Life cycle

• The old fragment object is destroyed when the fragment switch, and the new fragment object is created

Low version compatible

• There are APIs in the Support-v4.jar package, which means that fragment can be run in the low version emulator

Animated frame Animations

A picture is constantly switched to create an animated effect

• In the drawable directory, define the XML file, the child node is animation-list, where you define the picture to display and the length of time each picture is displayed

  <animation-list xmlns:android="http://schemas.android.com/apk/res/android" android:oneshot="false">    <item android:drawable="@drawable/g1" android:duration="200" />    <item android:drawable="@drawable/g2" android:duration="200" />    <item android:drawable="@drawable/g3" android:duration="200" /></animation-list>

• Play frame animations on the screen

  ImageView iv = (ImageView) findViewById(R.id.iv);//把动画文件设置为imageView的背景iv.setBackgroundResource(R.drawable.animations);AnimationDrawable ad = (AnimationDrawable) iv.getBackground();//播放动画        ad.start();

Motion Tweens

• When the original form becomes a new form, the resulting animation is called a motion tween, in order to transition the deformation process.
• Displacement, rotation, scaling, transparency

Displacement:

• Parameter 10 refers to the start coordinate of X, but does not refer to the position of the X coordinate of the screen, but the real x + 10 of the ImageView.

• Parameter 150 refers to the end coordinate of x, whose value is ImageView's true x + 150

  //创建为位移动画对象，设置动画的初始位置和结束位置TranslateAnimation ta = new TranslateAnimation(10, 150, 20, 140);

• The starting position of the x-coordinate, if relative to yourself, is 0.5f, then the starting coordinates are true X + 0.5 * IV width
• The end position of the X coordinate, if passed in 2, then the end coordinate is the width of the real x + 2 * IV
• The start position of the y-coordinate, if passed in 0.5f, then the starting coordinates are true Y + 0.5 * IV height

• The end position of the y-coordinate, if passed in 2, then the end coordinate is true y + 2 * IV height

  TranslateAnimation ta = new TranslateAnimation(Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 2, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 2);

• Settings related to animation playback

  //设置动画持续时间ta.setDuration(2000);//动画重复播放的次数ta.setRepeatCount(1);//动画重复播放的模式ta.setRepeatMode(Animation.REVERSE);//动画播放完毕后，组件停留在动画结束的位置上ta.setFillAfter(true);//播放动画iv.startAnimation(ta);

Scaling:

• Parameter 0.1f indicates that the starting width of the animation is 0.1 times times the true width
• Parameter 4 indicates that the end width of the animation is 4 times times the true width

• The center point of the zoom is in the upper left corner of the IV

  ScaleAnimation sa = new ScaleAnimation(0.1f, 4, 0.1f, 4);

• Parameters 0.1f and 4 have the same meaning as above
• Change the center point of the zoom: Incoming two 0.5f, the type is relative to itself, these two parameters change the center point of the zoom
• Center point x Coordinate = true x + 0.5 * IV width

• Center point Y coordinate = true y + 0.5 * IV height

  Scaleanimation sa = new Scaleanimation (0.1f, 4, 0.1f, 4, animation.relativeto self, 0.5f, animation.relative to self, 0.5f);

Transparent:

• 0 is fully transparent and 1 is completely opaque

  AlphaAnimation aa = new AlphaAnimation(0, 0.5f);

Rotating:

• 20 indicates the angle of the IV at the beginning of the animation
• 360 indicates the angle of the IV at the end of the animation

• The center of the default rotation is in the upper left corner of IV

  RotateAnimation ra = new RotateAnimation(20, 360);

• 20,360 of the meaning is the same as above
• Specifies the center coordinate, relative to itself, the value is passed in 0.5, then the X coordinate of the center: true x + IV Width * 0.5

• Y coordinate of Center point: true y + IV Height * 0.5

  RotateAnimation ra = new RotateAnimation(20, 360, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);

All animations once take off

    //创建动画集合    AnimationSet set = new AnimationSet(false);    //往集合中添加动画    set.addAnimation(aa);    set.addAnimation(sa);    set.addAnimation(ra);    iv.startAnimation(set);

Property animations

• tweened animation, just an animation effect, the component is actually in the original position, XY did not change

Displacement:

• The first parameter, target, specifies the component to display the animation
• The second parameter, PropertyName, specifies which property of the component to change
• The third parameter, values, is a mutable parameter, which is the new value given to the property
• Incoming 0, representing x starting coordinates: current x + 0

• Pass in 100, which represents the x endpoint coordinates: current x + 100

  //具有get、set方法的成员变量就称为属性ObjectAnimator oa = ObjectAnimator.ofFloat(bt, "translationX", 0, 100) ;

Scaling:

• The third parameter specifies the scale of the scale
• 0.1 is starting from One-tenth of the original height.

• 2 is twice times the end of the original height

  ObjectAnimator oa = ObjectAnimator.ofFloat(bt, "scaleY", 0.1f, 2);

Transparent:

• Transparency, 0 is completely transparent, 1 is completely opaque

  ObjectAnimator oa = ObjectAnimator.ofFloat(bt, "alpha", 0.1f, 1);

Rotating

• rotation specifies that clockwise rotation
• 20 is the starting angle

• 270 is the end angle

  ObjectAnimator oa = ObjectAnimator.ofFloat(bt, "rotation", 20, 270);

• Property specified as RotationX is inverted vertically

• Property specified as RotationY is flipped horizontally

  ObjectAnimator oa = ObjectAnimator.ofFloat(bt, "rotationY", 20, 180);

Variable parameters

• The third parameter variable parameter can be passed in multiple parameters, can be used to achieve back displacement (rotation, scaling, transparency)

  ObjectAnimator oa = ObjectAnimator.ofFloat(bt, "translationX", 0, 70, 30, 100) ;

All animations once take off

    //创建动画师集合    AnimatorSet set = new AnimatorSet();    //设置要播放动画的组件    set.setTarget(bt);    //所有动画有先后顺序的播放    //set.playSequentially(oa, oa2, oa3, oa4);    //所有动画一起播放    set.playTogether(oa, oa2, oa3, oa4);    set.start();

dialog box OK Cancel dialog box

• Create a Dialog builder object similar to Factory mode

• AlertDialog.Builder builder = new Builder(this);

• Set the title and body

• builder.setTitle("警告");builder.setMessage("若练此功，必先自宫");

• Set OK and Cancel buttons

  builder.setPositiveButton("现在自宫", new OnClickListener() {    @Override    public void onClick(DialogInterface dialog, int which) {        // TODO Auto-generated method stub        Toast.makeText(MainActivity.this, "恭喜你自宫成功，现在程序退出", 0).show();    }});builder.setNegativeButton("下次再说", new OnClickListener() {    @Override    public void onClick(DialogInterface dialog, int which) {        // TODO Auto-generated method stub        Toast.makeText(MainActivity.this, "若不自宫，一定不成功", 0).show();    }});

• Using the Builder to create a dialog box object

  AlertDialog ad = builder.create();ad.show();

Single-selection dialog box

    AlertDialog.Builder builder = new Builder(this);    builder.setTitle("选择你的性别");

• Define a radio option

• final String[] items = new String[]{        "男", "女", "其他"};//-1表示没有默认选择//点击侦听的导包要注意别导错builder.setSingleChoiceItems(items, -1, new OnClickListener() {    //which表示点击的是哪一个选项    @Override    public void onClick(DialogInterface dialog, int which) {        Toast.makeText(MainActivity.this, "您选择了" + items[which], 0).show();        //对话框消失        dialog.dismiss();    }});builder.show();

Multi-Select dialog box

    AlertDialog.Builder builder = new Builder(this);    builder.setTitle("请选择你认为最帅的人");

• The option to define multiple selections, because you can select multiple, so you need a Boolean array to record which options are selected

• final String[] items = new String[]{        "赵帅哥",        "赵师哥",        "赵老师",        "侃哥"};//true表示对应位置的选项被选了final boolean[] checkedItems = new boolean[]{        true,        false,        false,        false,};builder.setMultiChoiceItems(items, checkedItems, new OnMultiChoiceClickListener() {    //点击某个选项，如果该选项之前没被选择，那么此时isChecked的值为true    @Override    public void onClick(DialogInterface dialog, int which, boolean isChecked) {        checkedItems[which] = isChecked;    }});builder.setPositiveButton("确定", new OnClickListener() {    @Override    public void onClick(DialogInterface dialog, int which) {        StringBuffer sb = new StringBuffer();        for(int i = 0;i < items.length; i++){            sb.append(checkedItems[i] ? items[i] + " " : "");        }        Toast.makeText(MainActivity.this, sb.toString(), 0).show();    }});builder.show();

Progress Bar dialog box

• The Progress Bar dialog box can be directly new

  final ProgressDialog pd = new ProgressDialog(this);

• Sets the style of the progress bar, which can be rotated or a horizontal progress bar

  pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

• pd.setTitle("正在加载，请稍后...")//设置进度条进度值的最大值pd.setMax(200);pd.show();//开启子线程改变进度条的进度值Thread t = new Thread(){    @Override    public void run() {        // TODO Auto-generated method stub        super.run();        for (int i = 0; i < 200; i++) {            try {                sleep(30);            } catch (InterruptedException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }            //改变进度值            pd.setProgress(i);        }        pd.dismiss();    }};t.start();

Basics of Android App development: new features