新手安卓常用的一些属性教程（总会有你要的）

new Handler(Looper.getMainLooper()).post({}}  操作布局

        

        android:usesCleartextTraffic="true"  //明文传输
        
        允许使用浏览器
        <uses-permission android:name="android.permission.INTERNET"/>
        
        允许使用网络
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>


<activity  android:name=".view.HomeView"/> 加载文件


文件跳转
Intent intent = new Intent(MainActivity.this, HomeView.class);
startActivity(intent);
finish(); // 销毁当前Activity

弹窗
Toast.makeText(MainActivity.this, "验证码错误",Toast.LENGTH_SHORT).show();




hint 操作显示默认的东西
  

随机数
Random random = new Random();
int i = random.nextInt(10000);





返回上一级
super.onBackPressed();



动态布局
LayoutInflater inflater = LayoutInflater.from(this);
  GridView parent = findViewById(R.id.constraintLayout3);

parent.removeAllViews();
parent.addView(inflater.inflate(R.layout.index1,parent,false));



设置只允许使用3个字符和只可以输入数字类型

android:inputType="number"
android:maxLength="3"


多选框
<RadioGroup
    android:id="@+id/radioGroup2"
>
    <RadioButton
        android:checked="true"
        android:text="男" />

    <RadioButton
        android:text="女" />
</RadioGroup>

获取多选的按钮//        获取按钮组选中的值
        RadioGroup radioGroup = findViewById(R.id.radioGroup2);
        RadioButton r1=  findViewById(radioGroup.getCheckedRadioButtonId());


设置下拉框数据

    Spinner spinner2 = findViewById(R.id.spinner_location2);
    String[] data = {"c1", "c2", "c3", "Item 4", "Item 5"};
    // 创建一个ArrayAdapter并设置数据源
    ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, data);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_item);

    spinner2.setAdapter(adapter);
//获取选中的值
    String selectedItem = (String) spinner2.getSelectedItem(); 
    
    
    
下面的框：
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/index"
        android:title="Index"
        android:icon="@drawable/home"
        />
</menu>

布局
public class UserFragment extends Fragment {
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.user_f,container,false);
    }
}
        
        
 路由跳转
        
BottomNavigationView bot= findViewById(R.id.bot);
if(savedInstanceState==null){
    getSupportFragmentManager().beginTransaction().replace(R.id.f1,new indexFragment()).commit();
}

bot.setOnItemSelectedListener(item -> {
    Fragment fragment=null;
    switch (item.getItemId()){
        case R.id.index:
            fragment=new indexFragment();

            break;
        case R.id.shoppy:
            fragment=new ShoppyFragment();
            break;

        case R.id.user:
            fragment=new UserFragment();
            break;
    }

   getSupportFragmentManager().beginTransaction().replace(R.id.f1,fragment).commit();
    return true;
});  




请求
  
    public static String post(String key, RequestBody body) throws IOException {

        User zs = new User("admin", "1232");

        JSONObject s1 = new JSONObject();
        try {
            s1.put("username", zs.getUsername());
            s1.put("password", zs.getPassword());
        }catch (JSONException e) {
            e.printStackTrace();
        }

        //拼接完整的url
//        String path =" http://10.5.127.8:8080/shoppy";
        String path ="https://c.anzzm7.top/user";
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(path)
//                .post(body)
                .post(RequestBody.create(MediaType.parse("application/json"), s1.toString()))  // 将JSON格式的字符串作为请求体发送
                // token验证，也可以使用BirdgeInterceptor拦截器进行设置
                // .header("token", user.getString("token", ""))
                .build();
        Response response = client.newCall(request).execute();
        if (!response.isSuccessful())
            throw new IOException("Unexpected code " + response);  // 一般都是返回401、404一些异常，可以自己定义方法进行处理
        String resp = response.body().string();
        return resp;
    }

    
    
    
 username.setOnFocusChangeListener  失去焦点事件
 
 
 
 
 
 
 请求
public static String post(String url, JSONObject js) throws IOException {
        //拼接完整的url
        String path ="http://text1.00000.work/"+url;
//        String path ="https://c.anzzm7.top/user";
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(path)
//                .post(body)
                .post(RequestBody.create(MediaType.parse("application/json"),js.toString()))  // 将JSON格式的字符串作为请求体发送
                // token验证，也可以使用BirdgeInterceptor拦截器进行设置
                // .header("token", user.getString("token", ""))
                .build();
        Response response = client.newCall(request).execute();
        if (!response.isSuccessful())
            throw new IOException("Unexpected code " + response);  // 一般都是返回401、404一些异常，可以自己定义方法进行处理
        String resp = response.body().string();
        return resp;
    }


 转图片
    public static void loadImageFromUrl(String imageUrl, ImageView imageView) {
        new Thread(() -> {
        try {
            URL url = new URL(imageUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            InputStream input = connection.getInputStream();
            final Bitmap bitmap = BitmapFactory.decodeStream(input);

            // 在 UI 线程更新 ImageView
            imageView.post(() -> imageView.setImageBitmap(bitmap));

        } catch (IOException e) {
            e.printStackTrace();
        }
        }).start();
    }
    
    
    传文件
    public static String uploadFileImage(Uri imageUri,InputStream stream ) throws IOException {
    File file = new File(imageUri.getPath());  // 替换为您要上传的文件的路径

    System.out.println("文件名称"+ file.getName());

    String url = "https://file.00000.work:11001/test/upload" ;
    OkHttpClient client = new OkHttpClient();

    RequestBody requestBody = new MultipartBody.Builder()
            .setType(MultipartBody.FORM)
            .addFormDataPart("file", file.getName(), RequestBody.create(MediaType.parse("application/octet-stream"), file))
            .addFormDataPart("bucketName", "my-bucketname")
            .addFormDataPart("userName", "zhangsan")
            .build();

    Request request = new Request.Builder()
            .url(url)
            .post(requestBody)
            .build();

    try (Response response = client.newCall(request).execute()) {
        if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);
        return response.body().string();
    }
}

    

    菜单    
 getSupportFragmentManager().beginTransaction().replace(R.id.linearLayout,new IndexFragment()).commit();
 BottomNavigationView bottom = findViewById(R.id.bottom);
 bottom.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
     @Override
     public boolean onNavigationItemSelected(@NonNull MenuItem item) {

         Fragment fragment=null;
         switch (item.getItemId()) {
             case R.id.index:
                 fragment=new IndexFragment();

                 break;
             case R.id.shoppy:
                 fragment=new ShoppyFragment();

                 break;
             case R.id.user:
                 fragment=new UserFragment();
                 break;
         }

         getSupportFragmentManager().beginTransaction().replace(R.id.linearLayout,fragment).commit();

         return true;
     }
 });