Android UI模板设计

一、 设计需要的属性(组合模式)

1、 先在values文件夹下建立一个Values XML文件
2、 继承了RetativeLayout，并重写了它的构造方法
3、 在构造方法中，将所有获取的属性的值存在TypeArray中

    <declare-styleable name="Topbar">
        
        <attr name="title" format="string" />
        <attr name="titleTextSize" format="dimension" />
        <attr name="titleTextColor" format="color" />
        <attr name="leftText" format="string" />
        
        <attr name="leftBackground" format="reference|color" />
        <attr name="leftTextColor" format="color" />
        <attr name="rightText" format="string" />
        <attr name="rightBackground" format="reference|color" />
        <attr name="rightTextColor" format="color" />
    declare-styleable>

二、 实现一个我们的”View”

1、从TypeArray中取出相应的值，给予相应的变量
2、用layoutParams方法将控件添加到viewGroup，所有的属性都再layoutParams中设置，该变量就是控制按钮的控件以何种方式添加viewGroup中

public class Topbar extends RelativeLayout {

    private Button leftButton;
    private Button rightButton;
    private TextView tvTitle;

    //定义这些控件所需要的属性
    private int leftTextColor;
    private Drawable leftBackground;
    private String leftText;

    private int rightTextColor;
    private Drawable rightBackground;
    private String rightText;

    private float titleTextSize;
    private int titleTextColor;
    private String title;

    //将控件放入ViewGroup
    private LayoutParams leftParms;
    private LayoutParams rightParms;
    private LayoutParams titleParms;

    //因为需要自定义属性，所以用该方法
    public Topbar(Context context, AttributeSet attrs) {
        super(context, attrs);
        //设计并获取自定义属性
        TypedArray ta = context.obtainStyledAttributes(attrs,R.styleable.Topbar);
        leftTextColor = ta.getColor(R.styleable.Topbar_leftTextColor, 0);//找到所对应的属性的key(atts自定义属性文件集合中的对应属性)
        leftBackground = ta.getDrawable(R.styleable.Topbar_leftBackground);
        leftText = ta.getString(R.styleable.Topbar_leftText);

        rightTextColor = ta.getColor(R.styleable.Topbar_rightTextColor, 0);
        rightBackground = ta.getDrawable(R.styleable.Topbar_rightBackground);
        rightText = ta.getString(R.styleable.Topbar_rightText);

        titleTextSize = ta.getDimension(R.styleable.Topbar_titleTextSize, 0);
        titleTextColor = ta.getColor(R.styleable.Topbar_titleTextColor, 0);
        title = ta.getString(R.styleable.Topbar_title);
        //在使用完TypedArray变量后，进行回收（1、避免浪费资源；2、避免一些由于缓存所引起的错误）
        ta.recycle();

        leftButton = new Button(context);
        rightButton = new Button(context);
        tvTitle = new TextView(context);

        leftButton.setTextColor(leftTextColor);
        leftButton.setBackground(leftBackground);
        leftButton.setText(leftText);

        rightButton.setTextColor(rightTextColor);
        rightButton.setBackground(rightBackground);
        rightButton.setText(rightText);

        tvTitle.setTextColor(titleTextColor);
        tvTitle.setTextSize(titleTextSize);
        tvTitle.setText(title);
        tvTitle.setGravity(Gravity.CENTER);//显示文字居中

        setBackgroundColor(0xFFF59563);
        //传入长和宽
        leftParms = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
        //左对齐属性
        leftParms.addRule(RelativeLayout.ALIGN_PARENT_LEFT, TRUE);
        addView(leftButton, leftParms);

        rightParms = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
        rightParms.addRule(RelativeLayout.ALIGN_PARENT_RIGHT,TRUE);
        addView(rightButton,rightParms);

        titleParms = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,LayoutParams.MATCH_PARENT);
        titleParms.addRule(RelativeLayout.CENTER_IN_PARENT,TRUE);
        addView(leftButton,titleParms);
    }
}