float、double类型的数据格式化

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView text1 = (TextView) findViewById(R.id.text1);
TextView text2 = (TextView) findViewById(R.id.text2);
TextView text3 = (TextView) findViewById(R.id.text3);
TextView text4 = (TextView) findViewById(R.id.text4);
text1.setText(formaTranslate1(1345645654) + "***"
+ formaTranslate1(0.11111));
text2.setText(formaTranslate2(1345645654) + "***"
+ formaTranslate2(0.11111));
text3.setText(formaTranslate3(1345645654) + "***"
+ formaTranslate3(0.11111));
text4.setText(formaTranslate4(1345645654) + "***"
+ formaTranslate4(0.11111));
}

//科学计数法（整数没有保留4位小数，小数正常）

private double formaTranslate1(double f) {

BigDecimal bigDecimal = new BigDecimal(f);

bigDecimal = bigDecimal.setScale(4, BigDecimal.ROUND_HALF_UP);

return bigDecimal.doubleValue();

}

//整数正常，小于1的小数小数点左边的0不见了

private String formaTranslate2(double f) {

DecimalFormat dFormat = new DecimalFormat(“#.0000”);

return dFormat.format(f);

}

//都正常

private String formaTranslate3(double f) {

return String.format(“%.4f”, f);

}

//整数格式化了（每3位加一个逗号），其他正常

private String formaTranslate4(double f) {

NumberFormat nFormat = NumberFormat.getNumberInstance();

nFormat.setMinimumFractionDigits(4);

return nFormat.format(f);

}

}

运行结果：