Android studio demo_1_相冊

例子是相冊例子，可以顯示圖片，增加了4張png，按鈕切換；

使用了基本控件和佈局；

MainActivity的代碼

package com.yk.photo_show;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private ImageView image_viewById;
    private TextView name_viewById;
    private String[] name;
    private int[] imageid;
    private int i_num;
    private int i_length;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Log.d("init","ok");
        init();
    }

    private void init() {
        name = new String[]{"第1張","第2張","第3張","第4張"};
        imageid = new int[]{R.drawable.jiubc,R.drawable.kans,R.drawable.pikq,R.drawable.zuq};
        i_num = 0;
        i_length = name.length;//4
        Log.d("log", String.valueOf(i_length));

        image_viewById = findViewById(R.id.imageshow);
        name_viewById = findViewById(R.id.imagename);
        image_viewById.setImageResource(imageid[i_num]);
        name_viewById.setText(name[i_num]);

        findViewById(R.id.previous).setOnClickListener(this);
        findViewById(R.id.next).setOnClickListener(this);
    }
    private void update_image_fun() {
        image_viewById.setImageResource(imageid[i_num]);
        name_viewById.setText(name[i_num]);
    }
    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.previous:
                i_num--;
                if (i_num<0){
                    i_num=i_length-1;
                }
                break;
            case R.id.next:
                i_num++;
                if (i_num>=i_length){
                    i_num=0;
                }
                break;
        }
        update_image_fun();
        Log.v("log", String.valueOf(i_num));
        Log.d("log", String.valueOf(i_num));
        Log.i("log", String.valueOf(i_num));
        Log.w("log", String.valueOf(i_num));
        Log.e("log", String.valueOf(i_num));
    }
}

activity_main.xml 代碼

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.LinearLayoutCompat 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"
    android:orientation="vertical"
    android:layout_gravity="center"
    android:background="@color/colorPrimary"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/imageshow"
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/imagename"
        android:textSize="20dp"
        android:padding="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:layout_gravity="center"/>
    <android.support.v7.widget.LinearLayoutCompat
        android:orientation="horizontal"
        android:gravity="center"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <Button
            android:text="上一張"
            android:textSize="20dp"
            android:id="@+id/previous"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <Button
            android:text="下一張"
            android:textSize="20dp"
            android:id="@+id/next"
            android:layout_marginLeft="40dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </android.support.v7.widget.LinearLayoutCompat>

</android.support.v7.widget.LinearLayoutCompat>