Android实用代码七段（一）
1、 精确获取屏幕尺寸（例如：3.5、4.0、5.0寸屏幕）
DisplayMetrics dm = new DisplayMetrics();
ctx.getWindowManager().getDefaultDisplay().getMetrics(dm);
double diagonalPixels = Math.sqrt(Math.pow(dm.widthPixels, 2) + Math.pow(dm.heightPixels, 2));
return diagonalPixels / (160 * dm.density);
}
一般是7寸以上是平板
2、 判断是否是平板（官方用法）
return (context.getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_LARGE;
}
3、 文字根据状态更改颜色 android:textColor
< item android:color ="#53c1bd" android:state_selected ="true" />
< item android:color ="#53c1bd" android:state_focused ="true" />
< item android:color ="#53c1bd" android:state_pressed ="true" />
< item android:color ="#777777" />
</ selector >
放在res/color/目录下
4、背景色根据状态更改颜色 android:backgroup
< item android:state_selected ="true" >< shape >
<gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" />
</shape></item>
<item android:state_focused="true"><shape>
<gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" />
</shape></item>
<item android:state_pressed="true"><shape>
<gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" />
</shape></item>
<item><shape>
<gradient android:angle="0" android:centerColor="#00ff00" android:endColor="00ff00" android:startColor="00ff00" />
</shape></item>
</selector>
如果直接给背景色color会报错。
5、 启动APK的默认Activity
PackageManager pm = ctx.getPackageManager();
PackageInfo pi;
try {
pi = pm.getPackageInfo(packageName, 0);
Intent intent = new Intent(Intent.ACTION_MAIN, null);
intent.addCategory(Intent.CATEGORY_LAUNCHER);
intent.setPackage(pi.packageName);
List<ResolveInfo> apps = pm.queryIntentActivities(intent, 0);
ResolveInfo ri = apps.iterator().next();
if (ri != null) {
String className = ri.activityInfo.name;
intent.setComponent( new ComponentName(packageName, className));
ctx.startActivity(intent);
}
} catch (NameNotFoundException e) {
Log.e("startActivity", e);
}
}
7、计算字宽
TextPaint FontPaint = new TextPaint();
FontPaint.setTextSize(Size);
return FontPaint.measureText(text);
}
注意如果设置了textStyle，还需要进一步设置TextPaint。
本文转自博客园农民伯伯的博客，原文链接：Android实用代码七段（一），如需转载请自行联系原博主。
