本范例实现的是对界面中所有的控件一次性的设置字体样式。思路是找到父控件，然后遍历子控件。如果子控件是可以修改文字的控件，那么就设置文字。这用到了控件的继承，很多控件都是继承与textview的，所以将控件均转为textview，最后设置字体即可。

布局文件

 

MainActivity

package com.kale.font;import android.app.Activity;import android.graphics.Typeface;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.widget.Button;import android.widget.EditText;import android.widget.SeekBar;import android.widget.SeekBar.OnSeekBarChangeListener;import android.widget.TextView;public class MainActivity extends Activity {    private static int FLAG = 0;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                // Sets fonts for all        final Typeface mFont = Typeface.createFromAsset(getAssets(), "Roboto-Thin.ttf");        final ViewGroup root = (ViewGroup) findViewById(R.id.layout);        setFont(root, mFont,16);        FLAG = 1;//初始化完成后标志位为1，滑动滑块只修改字体大小。不重复指定字体了。                ((SeekBar) findViewById(R.id.seekBar)).setOnSeekBarChangeListener(new OnSeekBarChangeListener() {                        @Override            public void onStopTrackingTouch(SeekBar seekBar) {                            }                        @Override            public void onStartTrackingTouch(SeekBar seekBar) {                            }                        @Override            public void onProgressChanged(SeekBar seekBar, int progress,                    boolean fromUser) {                 setFont(root, mFont,progress);            }        });    }        /*     * Sets the font on all TextViews in the ViewGroup. Searches recursively for     * all inner ViewGroups as well. Just add a check for any other views you     * want to set as well (EditText, etc.)     */    public void setFont(ViewGroup group, Typeface font ,int textSize) {        int count = group.getChildCount();        View v;        for (int i = 0; i < count; i++) {            v = group.getChildAt(i);            if (v instanceof TextView || v instanceof EditText || v instanceof Button) {                if (FLAG == 0) {                    ((TextView) v).setTypeface(font);                }                ((TextView)v).setTextSize(textSize);            } else if (v instanceof ViewGroup)                setFont((ViewGroup) v, font,textSize);        }    }}

 

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