android - 按下按钮时应用程序随机从可绘制文件夹中选择图像

Question

我是 Android 开发的新手，我四处寻找可以组合的代码，但没有运气..

所以我想创建一个 Android 应用程序，当按下按钮时，它会从 drawable 文件夹中随机选择图像，并且你不能在 30 秒内再次按下按钮。

欢迎任何帮助。

随机 Activity .java

package com.example.no;

import java.util.Random;

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.ImageView; 
import android.view.Menu; 
import android.view.MenuInflater; 
import android.view.MenuItem; 
import android.view.View.OnClickListener; 

public class RandomImage extends Activity implements OnClickListener{ 
    private static final Random rgenerator = new Random(); 
    Integer [] mImageIds = { 
            R.drawable.img1, 
            R.drawable.img2, 
            R.drawable.img3, 
            }; 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    Integer q = mImageIds[rgenerator.nextInt(mImageIds.length)]; 
    ImageView iv = (ImageView) findViewById(R.id.imageviewyeah); 
    iv.setTag(q); 
    View nextButton = findViewById(R.id.next_image_button); 
    nextButton.setOnClickListener(this); 
} 

    @Override 
    public void onClick(View v) { 
    switch (v.getId()) { 
    case R.id.next_image_button: 
        Intent i = new Intent(this, RandomImage.class); 
        startActivity(i); 
        break; 
    } 
} 

    @Override 
        public boolean onCreateOptionsMenu (Menu menu) { 
                super.onCreateOptionsMenu(menu); 
                MenuInflater inflater = getMenuInflater(); 
                inflater.inflate(R.menu.main, menu); 
                return true; 
        } 
@Override 
public boolean onOptionsItemSelected (MenuItem item) { 
                switch (item.getItemId()) { 
                case R.id.action_settings: 
                        startActivity(new Intent(this, MainActivity.class)); 
                        return true; 
} 

return false; 
        } 

}

--activity_main.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 
    android:orientation="vertical" 
xmlns:android="http://schemas.android.com/apk/res/android" 
android:id="@+id/widget0" 
android:background="@drawable/bgi" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
    android:layout_gravity="center" > 
<ImageView 
        android:id="@+id/imageviewyeah" 
        android:tag="q" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:layout_gravity="center"> 
</ImageView> 
<Button 
        android:id="@+id/next_image_button" 
        android:text="Next Image" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:padding="10dip" 
        android:typeface="serif"/> 
</LinearLayout>

--

Answer 1

在声明中:

final Random rnd = new Random();
ImageView img = null;
Button btnRandom = null;

在主 Activity 中:

@Override
protected void onCreate(
    final Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);

    setContentView(R.layout.rnd_images);
    img = (ImageView) findViewById(R.id.imgRandom);
    btnRandom = (Button) findViewById(R.id.btnRandom);
}

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;
    }
}

public void clickHandler(final View v)
{
    switch(v.getId())
    {
        case R.id.btnRandom:
        {
            if (!btnRandom.isEnabled())
            {
                return;
            }

            // 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()))
            );
            btnRandom.setEnabled(false);

            new CountDownTimer(5000, 1000) // Wait 5 secs, tick every 1 sec
            {
                @Override
                public final void onTick(final long millisUntilFinished)
                {
                    btnRandom.setText("Wait: " + (millisUntilFinished / 1000));
                }
                @Override
                public final void onFinish()
                {
                    btnRandom.setText("Change!");
                    btnRandom.setEnabled(true);
                }
            }.start();

            break;
        }
    }
}

布局(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"
    />
    <Button
        android:id="@+id/btnRandom"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:text="Change!"
        android:onClick="clickHandler"
    />
</RelativeLayout>

[编辑]

我修改了布局中的按钮定义。我看到没有遵守时间安排，所以，我要修复它。

我还修复了代码以正确处理时间。

[重新编辑]

我修改了 clickHandler 函数以显示剩余的宽限期并在点击后第一次触发，没有任何延迟