编码设置FrameLayout子View的layout_gravity,gravity

来源：互联网发布：python idle使用技巧编辑：程序博客网时间：2024/06/05 10:13

方法：

setLayoutParams: 用来设置带有layout前缀的属性，所有子View attach到父View都会有LayoutParams，但是parentView.addView(childView)之前，childView.getLayoutParams（）会返回null。

根据源码：

    public void setLayoutParams(ViewGroup.LayoutParams params) {        if (params == null) {            throw new NullPointerException("Layout parameters cannot be null");        }        mLayoutParams = params;        resolveLayoutParams();        if (mParent instanceof ViewGroup) {            ((ViewGroup) mParent).onSetLayoutParams(this, params);        }        requestLayout();    }

可以看出要想使setlayoutParams生效，必须有父View，就是调用了addView

setGravity：用来设置内部的子View。

代码：

mTitleBar = new LinearLayout(context);    mTitleBar.setLayoutParams(new LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, 200));    mTitleBar.setBackgroundColor(Color.BLACK);        TextView textView = new TextView(context);    textView.setText("lfjasodijfaodjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj");    mTitleBar.addView(textView);    LinearLayout.LayoutParams textParams = new LinearLayout.LayoutParams(    ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.WRAP_CONTENT);    textView.setLayoutParams(textParams);    textView.setGravity(Gravity.END);        mBottomBar = new LinearLayout(context);    TextView bottomTV = new TextView(context);    bottomTV.setText("lfjasodijfaodjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj");    mBottomBar.addView(bottomTV);        this.addView(mTitleBar);    this.addView(mBottomBar);        FrameLayout.LayoutParams frameLayoutParams = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, 70);    frameLayoutParams.gravity = Gravity.TOP;    mTitleBar.setLayoutParams(frameLayoutParams);        FrameLayout.LayoutParams frameLayoutParams2 = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, 70);    frameLayoutParams2.gravity = Gravity.BOTTOM;    mBottomBar.setLayoutParams(frameLayoutParams2);

效果是：

两个TextView，在两个LinearLayout中，上面的TextView gravity是右边。两个LinearyLayout在FrameLayout中layout_gravity一个Top一个Bottom

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