安卓开发-Android Studio-前端-引入图片

安卓开发-Android Studio-前端引入图片

1· 新建一个Activity 名为ImageViewActivity

2.在activity_main.xml里面设置按钮即

3.在MainActivity里面声明ImageViewActivity 并设置点击事件。

package com.example.ayb.helloworld;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    private Button mBtnTextView;
    private Button mBtnButton;
    private Button mBtnEditText;
    private Button mBtnRadioButton;
    private Button mBtnCheckBox;
    private Button mBtnImageView;//此处为声明

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mBtnTextView = findViewById(R.id.btn_textview);
        mBtnButton = findViewById(R.id.btn_button);
        mBtnEditText = findViewById(R.id.btn_edittext);
        mBtnRadioButton = findViewById(R.id.btn_radiobutton);
        mBtnCheckBox = findViewById(R.id.btn_checkbox);
        mBtnImageView = findViewById(R.id.btn_imageview);//根据Id找到ImageView
        setOnClickListener();
    }
    private void setOnClickListener(){
        OnClick onClick = new OnClick();
        mBtnTextView.setOnClickListener(onClick);
        mBtnRadioButton.setOnClickListener(onClick);
        mBtnEditText.setOnClickListener(onClick);
        mBtnButton.setOnClickListener(onClick);
        mBtnCheckBox.setOnClickListener(onClick);
        mBtnImageView.setOnClickListener(onClick);//设置点击事件
    }

    private class  OnClick  implements View.OnClickListener{

        @Override
        public void onClick(View v){
            Intent intent = null;
            switch (v.getId()){
                case R.id.btn_textview:
                    intent = new Intent(MainActivity.this,TextViewActivity.class);
                    break;
                case R.id.btn_button:
                    intent = new Intent(MainActivity.this,ButtonActivity.class);
                    break;
                case R.id.btn_edittext:
                    intent = new Intent(MainActivity.this, EditTextActivity.class);
                    break;
                case R.id.btn_radiobutton:
                    intent = new Intent(MainActivity.this, RadioButtonActivity.class);
                    break;
                case R.id.btn_checkbox:
                    intent = new Intent(MainActivity.this, CheckBoxAcitivity.class);
                    break;
                case R.id.btn_imageview:
                    intent = new Intent(MainActivity.this, ImageViewActivity.class);
                    break;
            }
            startActivity(intent);
        }
    }
}

4.在ImageViewActivity里面引入本地图片

id 即设置图片框id 方便添加事件

layout_width/height 即设置图片框高度和宽度

background 设置图片框背景颜色

src 引入本地图片图片存放在drawable-v24中

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="15dp">

    <ImageView
        android:id="@+id/iv_1"
        android:layout_width="330dp"
        android:layout_height="200dp"
        android:background="#f99999"
        android:src="@drawable/tutu"
        android:scaleType="fitXY"
        android:layout_marginTop="10dp"
        />

    <ImageView
        android:id="@+id/iv_2"
        android:layout_width="300dp"
        android:layout_height="200dp"
        android:src="@drawable/tutu"
        android:layout_below="@id/iv_1"
        android:scaleType="fitCenter"
        />

    <ImageView
        android:id="@+id/iv_3"
        android:layout_width="210dp"
        android:layout_height="200dp"
        android:layout_below="@id/iv_2"
        android:scaleType="centerCrop"
        android:src="@drawable/tutu" />

</RelativeLayout>

scaleType则是填充图片框有三种方法 fitXY 拉伸是指完全填充 fitCenter 使之居中填充 CenterCrop 使之裁剪填充

例如