第一步：创建工程：
第二步：编写前端页面：
找到content_main.xml:
具体代码如下：
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<fragment
android:id="@+id/nav_host_fragment_content_main"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
android:visibility="invisible"
app:defaultNavHost="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0"
app:navGraph="@navigation/nav_graph" />
<TextView
android:id="@+id/textView"
android:layout_width="168dp"
android:layout_height="93dp"
android:text="@string/label"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.497"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.269" />
<TextView
android:id="@+id/textView2"
android:layout_width="63dp"
android:layout_height="26dp"
android:layout_marginStart="52dp"
android:layout_marginTop="32dp"
android:text="身高(cm)"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView" />
<!--app代表上下左右位置-->
<EditText
android:id="@+id/editTextTextPersonName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:ems="10"
android:hint="@string/tips"
android:inputType="textPersonName"
android:minHeight="48dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.255"
app:layout_constraintStart_toEndOf="@+id/textView2"
app:layout_constraintTop_toBottomOf="@+id/textView" />
<TextView
android:id="@+id/textView3"
android:layout_width="60dp"
android:layout_height="23dp"
android:layout_marginStart="52dp"
android:layout_marginTop="48dp"
android:text="体重(kg)"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView2" />
<EditText
android:id="@+id/editTextTextPersonName2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:ems="10"
android:hint="@string/tips2"
android:inputType="textPersonName"
android:minHeight="48dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toEndOf="@+id/textView3"
app:layout_constraintTop_toBottomOf="@+id/editTextTextPersonName" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="184dp"
android:onClick="onClick"
android:text="@string/count"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView"
app:layout_constraintVertical_bias="0.192" />
<TextView
android:id="@+id/textView4"
android:layout_width="300dp"
android:layout_height="35dp"
android:layout_marginTop="12dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@+id/editTextTextPersonName2" />
</androidx.constraintlayout.widget.ConstraintLayout>第三步：编写后端：
找到MainActivity类：里面需要注意编写的每一个组件的id需要一致。
package com.example.myapplication777;
import android.icu.text.Edits;
import android.os.Bundle;
import com.google.android.material.snackbar.Snackbar;
import androidx.appcompat.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;
import com.example.myapplication777.databinding.ActivityMainBinding;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private AppBarConfiguration appBarConfiguration;
private ActivityMainBinding binding;
//计算
public float height=0f;
public float weight=0f;
public float result=0f;
//输入框的属性
EditText editText1=null;
EditText editText2=null;
TextView textView =null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
setSupportActionBar(binding.toolbar);
//实例化
//身高体重
editText1=(EditText)findViewById(R.id.editTextTextPersonName);
editText2=(EditText)findViewById(R.id.editTextTextPersonName2);
//显示结果
textView=(TextView)findViewById(R.id.textView4);
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
appBarConfiguration = new AppBarConfiguration.Builder(navController.getGraph()).build();
NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
binding.fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
//计算
public void onClick(View view){
Log.d("TAG","--------点击了计算按钮-------");
height= Float.parseFloat(editText1.getText().toString());
height=height/100f;
weight= Float.parseFloat(editText2.getText().toString());
result=weight/(height*height);
textView.setText("您的BMI值为："+result);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public boolean onSupportNavigateUp() {
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
return NavigationUI.navigateUp(navController, appBarConfiguration)
|| super.onSupportNavigateUp();
}
}第四步：调试
如果因为gradle版本的问题可以看前面一期。
第五步：安装到手机
进行安装即可，出现安卓手机版本问题需要调一下sdk。最后手机上安装成功。
