android:layout_width=“match_parent”
android:layout_height=“wrap_content”
android:gravity=“left”
android:text=“体重（KG）”
android:textSize=“25sp”
/>
<EditText
android:id=“@+id/tz”
android:layout_width=“match_parent”
android:layout_height=“wrap_content”
android:hint=“请输入你的体重：”
/>
<Button
android:id=“@+id/btn1”
android:layout_width=“match_parent”
android:layout_height=“wrap_content”
android:text=“计算BMI”
android:textSize=“30sp”
/>
<TextView
android:layout_width=“match_parent”
android:layout_height=“wrap_content”
android:gravity=“left”
android:text=“你的BMI总数为”
android:textSize=“25sp”
/>
<EditText
android:id=“@+id/BMI”
android:layout_width
=“match_parent”
android:layout_height=“wrap_content”/>
<ImageView
android:layout_width=“wrap_content”
android:layout_height=“wrap_content”
android:background=“@drawable/bmi”
/>
Java功能实现运行代码
调用获得xml布局文件的一系列属性，对输入的身高和体重进行运算并把结果给set到控件BIM行上，以及运用Toast进行短暂的提示！
package com.example.bmiapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private Button btn1;
private EditText heightText,weightText,resText;
// private TextView resText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn1 = (Button) findViewById(R.id.btn1);
heightText = (EditText) findViewById(R.id.sg);
weightText = (EditText) findViewById(R.id.tz);
resText = (EditText) findViewById(R.id.BMI);
btn1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//得到身高体重
String height = heightText.getText().toString();
String weight = weightText.getText().toString();
double result = 0, heightNum = 0, weightNum = 0;
if(!height.isEmpty()&&!weight.isEmpty()) {
heightNum = Double.parseDouble(height);
weightNum = Double.parseDouble(weight);
result = weightNum / (heightNum*heightNum);
TextView BMI = (TextView) findViewById(R.id.BMI);
BMI.setText("Your BMI is " + result);
}
if (result <= 18.4) {
Toast.makeText(MainActivity.this, “你的体重有点偏瘦哦”, Toast.LENGTH_SHORT).show();
} else if (result<= 23.9 && result> 18.5) {
Toast.makeText(MainActivity.this, “你的体重正常哦”, Toast.LENGTH_SHORT).show();
} else if (result<= 27.9 && result> 24) {
Toast.makeText(MainActivity.this, “你的体重有点过重哦”, Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(MainActivity.this, “你的体重有点肥胖哦”, Toast.LENGTH_SHORT).show();
}