Android内存优化操作方法梳理总结

class MemoryActivity : AppCompatActivity() {
    compaNIOn object {
        var test: Test? = null
    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_memory)
        test = Test()
    }
    inner class Test {
    }
}

class MemoryActivity : AppCompatActivity() {
    companion object {
        var test: Test? = null
    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_memory)
        test = Test()
    }
     //Kotlin的静态内部类
     class Test {
    }
}

class SingleTon private constructor(val context: Context) {
    companion object {
        private var instance: SingleTon? = null
        fun getInstance(context: Context) =
            if (instance == null) SingleTon(context) else instance!!
    }
}

class MemoryActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_memory)
        SingleTon.getInstance(this)
    }
}

class SingleTon private constructor(context: Context) {
    private var context: Context
    init {
        this.context = context.applicationContext
    }
    companion object {
        private var instance: SingleTon? = null
        fun getInstance(context: Context) =
            if (instance == null) SingleTon(context) else instance!!
    }
}

class MemoryActivity : AppCompatActivity() {
    private val tag = javaClass.simpleName
    private val handler = object : Handler(Looper.getMainLooper()) {
        override fun handleMessage(msg: Message) {
            Log.i(tag, "handleMessage:$msg")
        }
    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_memory)
        thread(start = true) {
            handler.sendEmptyMessageDelayed(1, 10000)
        }
    }
}

class MemoryActivity : AppCompatActivity() {
    companion object {
        private const val tag = "uncle"
    }
    private lateinit var handler: Handler
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_memory)
        handler = MyHandler(this)
        thread(start = true) {
            handler.sendEmptyMessageDelayed(1, 10000)
        }
    }
    class MyHandler(activity: Activity) : Handler(Looper.getMainLooper()) {
        private val reference = WeakReference(activity)
        override fun handleMessage(msg: Message) {
            super.handleMessage(msg)
            if (reference.get() != null) {
                Log.i(tag, "handleMessage:$msg")
            }
        }
    }
}

class GlobalData {
    companion object {
        val activityStack = Stack<Activity>()
    }
}

class MemoryActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_memory)
        GlobalData.activityStack.push(this)
    }
}

        if (bitmap != null && !bitmap.isRecycled) {
            bitmap.recycle()
            bitmap = null
        }

        var bitmap: Bitmap? = null
        try {
            bitmap = BitmapFactory.decodeFile(filePath)
            imageView.setImageBitmap(bitmap)
        } catch (e: OutOfMemoryError) {
            //捕获异常
        }
        if (bitmap == null) {
            imageView.setImageDrawable(ContextCompat.getDrawable(this, R.drawable.picture))
        }

        val options = BitmapFactory.Options()
        //设置为true可以让解析方法禁止为bitmap分配内存，返回null,同时能获取到长宽值，从而根据情况进行压缩
        options.inJustDecodeBounds = true
        BitmapFactory.decodeResource(resources, R.drawable.large_picture, options)
        val imgHeight = options.outHeight
        val imgWidth = options.outWidth
        //通过改变inSampleSize的值来压缩图片
        var inSampleSize = 1
        //imgWidth为图片的宽,viewWidth为实际控件的宽
        if (imgHeight > viewHeight || imgWidth > viewWidth) {
            val heightRatio = round(imgHeight / viewHeight.toFloat()).toInt()
            val widthRatio = round(imgWidth / viewWidth.toFloat()).toInt()
            //选择最小比率作为inSampleSize的值，可保证最终图片的宽高一定大于等于目标的宽高
            inSampleSize = if (heightRatio < widthRatio) heightRatio else widthRatio
        }
        options.inSampleSize = inSampleSize
        //计算完后inJustDecodeBounds重置为false
        options.inJustDecodeBounds = false
        val bitmap = BitmapFactory.decodeResource(resources, R.drawable.large_picture, options)
        imageView.setImageBitmap(bitmap)