Question

我试图创建一个简单的手电筒应用程序，以学习Android开发。我试图得到它，以便当你点击光ImageView对象时，它会改变图像。但是现在它在调试器到达light.setImageResource（）时崩溃了。

    import android.support.v7.app.ActionBarActivity;
    import android.os.Bundle;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.widget.ImageView;


    public class flash extends ActionBarActivity {

        public Boolean on = false;

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

            ImageView light = (ImageView) findViewById(R.id.light);

            light.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {
                    ImageView light = (ImageView) findViewById(R.id.light);
                    if(on){
                        light.setImageResource(R.drawable.flash_off);
                        on = false;
                    }else{
                        light.setImageResource(R.drawable.flash_on);
                        on = true;
                    }
                }
            });
        }


        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.menu_flash, menu);
            return true;
        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();

            //noinspection SimplifiableIfStatement
            if (id == R.id.action_settings) {
                return true;
            }

            return super.onOptionsItemSelected(item);
        }
    }

它抛出的错误是

        --------- beginning of crash
    01-18 14:05:27.675    1953-1953/com.peterchappy.openflash E/AndroidRuntime﹕ FATAL EXCEPTION: main
        Process: com.peterchappy.openflash, PID: 1953
        java.lang.OutOfMemoryError: Failed to allocate a 51840012 byte allocation with 4194304 free bytes and 13MB until OOM

Answer 1

CRASH：
正如您的stacktrace所说：“java.lang。 OutOfMemoryError：无法分配51840012字节分配4194304空闲字节和13MB直到OOM” - 您尝试在视图上显示一个巨大的位图。你的手机不喜欢它。
两种解决方案：

缩小图片尺寸，使用较小的图片......然后重试！
或在您的应用标记中设置android:largeHeap="true"中的Manifest。它会增加您的堆大小并避免OutOfMemory错误，但您的应用程序可能会滞后。

TIPS：
您不需要第二行，您重新找到 ID的视图尝试使用global变量检索其ID，如下所示，并使用getResources()方法获取您的drawable：

public class flash extends ActionBarActivity {

    ImageView light; // init your variable
    public Boolean on = false;

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

        // find its id with its global variable
        light = (ImageView) findViewById(R.id.light);

        light.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                if(on){
                    // get the resource drawable
                    light.setImageResource(
                        getResources().getDrawable(R.drawable.flash_off));
                    on = false;
                }else{
                    light.setImageResource(
                        getResources().getDrawable(R.drawable.flash_on));
                    on = true;
                }
            }
        });
    }
    ...
}

Answer 2

您不需要在处理程序

中声明变量light

public class flash extends ActionBarActivity {

        public Boolean on = false;
        ImageView light;

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

            light = (ImageView) findViewById(R.id.light);

            light.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {
                    if(on){
                        light.setImageResource(R.drawable.flash_off);
                        on = false;
                    }else{
                        light.setImageResource(R.drawable.flash_on);
                        on = true;
                    }
                }
            });
        }

应用程序在更改ImageView时崩溃

2 个答案: