Android 如何在图像视图上显示随机图像
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How To Display Random images on image view
提问by Anonymous
Could someone please help me out with a code to randomly display a picture from the my drawings folder? i am new to java so i have no idea how to do it. Any help will be appreciated. My Requirements are:- 1.Display Random image (image should change on each start up) 2.that's all
有人可以帮我提供一个代码来随机显示我的图纸文件夹中的图片吗？我是 Java 新手，所以我不知道该怎么做。任何帮助将不胜感激。我的要求是：- 1.显示随机图像（图像应在每次启动时更改）2.仅此而已
import java.util.Random;
import java.util.Random;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
public class MainMenu extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_menu);
}
public void openNewActivity(View view) {
Intent intent = new Intent(this,MainActivity.class);
startActivity(intent);//button to open main
}
public void browser(View view) {
Intent intent = new Intent(this,Browser.class);
startActivity(intent);//button to open browser
}
final Random rnd = new Random();
{
setContentView(R.layout.activity_main_menu);
final ImageView img = (ImageView) findViewById(R.id.imgRandom);
// I have 3 images named img_0 to img_2, so...
final String str = "img_" + rnd.nextInt(9);
img.setImageDrawable
(
getResources().getDrawable(getResourceID(str, "drawable",
getApplicationContext()))
);
}
protected final static int getResourceID
(final String resName, final String resType, final Context ctx)
{
final int ResourceID =
ctx.getResources().getIdentifier(resName, resType,
ctx.getApplicationInfo().packageName);
if (ResourceID == 0)
{
throw new IllegalArgumentException
(
"No resource string found with name " + resName
);
}
else
{
return ResourceID;
}
}
}
回答by Phant?maxx
Put some images named img_0 to img_n in your res/drawable folder
将一些名为 img_0 的图像放入 res/drawable 文件夹中的 img_n
Layout (res/layout/rnd_images.xml):
布局（res/layout/rnd_images.xml）：
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity"
>
<ImageView
android:id="@+id/imgRandom"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
/>
</RelativeLayout>
Code:
代码：
package com.example.app;
import java.util.Random;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.ImageView;
public class MainActivity
extends Activity
{
final Random rnd = new Random();
@Override
protected void onCreate(
final Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.rnd_images);
final ImageView img = (ImageView) findViewById(R.id.imgRandom);
// I have 3 images named img_0 to img_2, so...
final String str = "img_" + rnd.nextInt(2);
img.setImageDrawable
(
getResources().getDrawable(getResourceID(str, "drawable",
getApplicationContext()))
);
}
protected final static int getResourceID
(final String resName, final String resType, final Context ctx)
{
final int ResourceID =
ctx.getResources().getIdentifier(resName, resType,
ctx.getApplicationInfo().packageName);
if (ResourceID == 0)
{
throw new IllegalArgumentException
(
"No resource string found with name " + resName
);
}
else
{
return ResourceID;
}
}
}
Note that you have to set rnd.nextInt(2) to rnd.nextInt(Max - 1), since rnd starts from 0
请注意，您必须将 rnd.nextInt(2) 设置为 rnd.nextInt(Max - 1)，因为 rnd 从 0 开始
[UPDATE]
[更新]
The layout name must match that in setContentView.
So, if you have (why?) this:
布局名称必须与 setContentView 中的名称匹配。
所以，如果你有（为什么？）这个：
setContentView(R.layout.activity_main);
in your MainActivity.java/onCreate, then rename the layout "activity_main.xml"
在 MainActivity.java/onCreate 中，然后重命名布局“activity_main.xml”
OR, better, USE MY CODE AS IS.
或者，更好的是，按原样使用我的代码。
It works without modifications.
它无需修改即可工作。
[UPDATE]
[更新]
Check this line:
检查这一行：
final Random rnd = new Random();
It requires the following import:
它需要以下导入：
import java.util.Random;
My code works as is. I tested it before giving it to you.
Just place my layout in res/layout, the images in res/drawable and the MainActivity.java to replace the default one.
我的代码按原样工作。我在给你之前测试了它。
只需将我的布局放在 res/layout 中，将图像放在 res/drawable 和 MainActivity.java 中以替换默认设置。
Please, notice that the images names MUST be "img_#" where # is a number.
This number must be 0 to (max - 1).
请注意，图像名称必须是“img_#”，其中 # 是一个数字。
此数字必须是 0 到（最大 - 1）。
Or give names like "my_city_#" or whatever.
But then you must update the java code to match these names.
或者给出诸如“my_city_#”之类的名称。
但随后您必须更新 java 代码以匹配这些名称。
