UI组件之弹出组件

• Toast是一个消息提示组件
• 设置显示的位置
• 自定义显示的内容（图片+文本）
• 简单封装

---

layout_toast自定义布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="#99000000"
    android:gravity="center"
    >

    <LinearLayout
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:orientation="vertical"
        android:gravity="center"
    >

        <ImageView
            android:id="@+id/iv_toast"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:scaleType="fitCenter"

            />


        <TextView
            android:id="@+id/tv_toast"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            android:textColor="#ffffff"
            android:layout_marginTop="10dp"
            />
    </LinearLayout>


</LinearLayout>

---

新建一个包util，搞一个toast的封装方法

package com.example.test0508.util;

import android.content.Context;
import android.widget.Toast;

public class ToastUtil {
    public static Toast mToast;
    public static void showMessage(Context context, String msg){
        if (mToast == null){
            mToast = Toast.makeText(context,msg,Toast.LENGTH_SHORT);
        }else {
            mToast.setText(msg);
        }
        mToast.show();
    }
}

---

TosatActivity以及页面布局文件

package com.example.test0508;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.example.test0508.util.ToastUtil;

public class ToastActivity extends AppCompatActivity {


    private Button mBtnToast1,mBtnToast2,mBtnToast3,mBtnToast4;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_toast);
        mBtnToast1 = findViewById(R.id.btn_text_toast1);
        mBtnToast2 = findViewById(R.id.btn_text_toast2);
        mBtnToast3 = findViewById(R.id.btn_text_toast3);
        mBtnToast4 = findViewById(R.id.btn_text_toast4);
        OnClick onClick = new OnClick();
        mBtnToast1.setOnClickListener(onClick);
        mBtnToast2.setOnClickListener(onClick);
        mBtnToast3.setOnClickListener(onClick);
        mBtnToast4.setOnClickListener(onClick);
    }

    class OnClick implements View.OnClickListener{

        @Override
        public void onClick(View view) {
            switch (view.getId()){
                case R.id.btn_text_toast1:
                    Toast.makeText(getApplicationContext(),"Toast",Toast.LENGTH_SHORT).show();
                    break;
                case R.id.btn_text_toast2:
                    //居中显示
                    Toast toastCenter = Toast.makeText(getApplicationContext(),"居中显示",Toast.LENGTH_SHORT);
                    toastCenter.setGravity(Gravity.CENTER,0,0);
                    toastCenter.show();
                    break;
                case R.id.btn_text_toast3:
                    //带图片
                    Toast toastCustom = new Toast(getApplicationContext());
                    LayoutInflater inflater = LayoutInflater.from(ToastActivity.this);
                    View v = inflater.inflate(R.layout.layout_toast,null);
                    ImageView imageView = v.findViewById(R.id.iv_toast);
                    TextView textView = v.findViewById(R.id.tv_toast);
                    imageView.setImageResource(R.drawable.xuegao);
                    textView.setText("雪糕啊");
                    toastCustom.setView(v);
                    toastCustom.show();
                    break;
                case R.id.btn_text_toast4:
                    ToastUtil.showMessage(getApplicationContext(),"封装好的msg");
                    break;
            }
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="10dp"
    android:orientation="vertical"
    >
    <Button
        android:id="@+id/btn_text_toast1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="默认"/>


    <Button
        android:id="@+id/btn_text_toast2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="改变位置"/>


    <Button
        android:id="@+id/btn_text_toast3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="带图片(自定义）"/>

    <Button
        android:id="@+id/btn_text_toast4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="封装Toast"/>
</LinearLayout>