一 、背景

使用自定义DialogFragment实现弹窗效果时，边缘透明图片作为背景图片，依然存在不透明背景；

QQ截图20180428154111.png

QQ截图20180428153910.png

二、实现

因为项目中多个地方使用到DialogFragment，所以稍作了一下封装：

import android.app.Dialog;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.DialogFragment;
import android.support.v7.app.AlertDialog;
import android.util.DisplayMetrics;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import butterknife.ButterKnife;
import butterknife.Unbinder;

/**
 * Created by Ljt on 2018/4/27
 */
public abstract class BaseDislogFragment extends DialogFragment {

    private boolean isShow = false;
    private Unbinder unbinder;

    public boolean isShow() {
        return isShow;
    }

    public void setShow(boolean show) {
        isShow = show;
    }

    /**
     * 显示弹窗信息
     * @param savedInstanceState
     * @param builder
     */
    protected abstract void displayDialog(Bundle savedInstanceState, AlertDialog.Builder builder);

    /**
     * 设置布局文件
     * @return
     */
    protected abstract int getLayoutId();

    protected abstract boolean isCanceledOnTouchOutside();

    protected abstract boolean isTransparent();

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
        View rootView = super.onCreateView(inflater, container, savedInstanceState);
        return rootView;
    }

    @Override
    public void onStart() {
        super.onStart();
        if (isTransparent()) {
            //设置背景半透明
            DisplayMetrics dm = new DisplayMetrics();
            getActivity().getWindowManager().getDefaultDisplay().getMetrics(dm);
            getDialog().getWindow().setLayout(dm.widthPixels, getDialog().getWindow().getAttributes().height);
            getDialog().getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        }

        //getDialog().setCancelable(false);//这个会屏蔽掉返回键
        getDialog().setCanceledOnTouchOutside(isCanceledOnTouchOutside());

    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        LayoutInflater inflater = getActivity().getLayoutInflater();
        final View view = inflater.inflate(getLayoutId(), null);
        unbinder = ButterKnife.bind(this, view);
        builder.setView(view);
        displayDialog(savedInstanceState,builder);
        return builder.create();
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        unbinder.unbind();
    }

    public void dismissDialog() {
        if (isShow) {
            this.dismiss();
        }
    }
}

所以事实上，这里最终使用的还是使用onCreateDialog()方法返回AlertDialog来呈现自定义布局弹窗；

主要的实现背景透明效果，使用如下代码：

 DisplayMetrics dm = new DisplayMetrics();
 getActivity().getWindowManager().getDefaultDisplay().getMetrics(dm);
 getDialog().getWindow().setLayout(dm.widthPixels, getDialog().getWindow().getAttributes().height);
 getDialog().getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));

BaseDialogFragment的子类使用起来就只关注与具体差异的实现就好了：

import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

//这里删除了部分带有APP报名路径的类的导入

import butterknife.BindView;

/**
 * Created by Ljt on 2018/4/26
 */
public class RewardDialogFragment extends BaseDislogFragment {

    @BindView(R.id.img_reward_bg)
    ImageView imgRewardBg;
    @BindView(R.id.tv_reward_sum)
    TextView tvRewardSum;
    @BindView(R.id.tv_reward_receive)
    TextView tvRewardReceive;
    @BindView(R.id.rl_reward_content)
    RelativeLayout rlRewardContent;
    @BindView(R.id.img_reward_close)
    ImageView imgRewardClose;

    private Callback callback;

    public interface Callback {
        void onClose();
        void onReceive();
    }

    public void setCallback(Callback pCallBack){
        this.callback = pCallBack;
    }

    public void show(FragmentManager fragmentManager) {
        if (this.isAdded())return;
        show(fragmentManager, "RewardDialogFragment");
        setShow(false);
        Settings.setFirstReward(false);
    }

    @Override
    protected void displayDialog(Bundle savedInstanceState, android.support.v7.app.AlertDialog.Builder builder) {
        imgRewardClose.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (callback != null)callback.onClose();
                dismiss();
            }
        });
        tvRewardReceive.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (callback != null)callback.onReceive();
                dismiss();
            }
        });
    }

    @Override
    protected int getLayoutId() {
        return R.layout.fragment_dialog_reward;
    }

    @Override
    protected boolean isCanceledOnTouchOutside() {
        return false;
    }

    @Override
    protected boolean isTransparent() {
        return true;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        callback = null;
    }

}

！！！请确认当中的AlertDialog使用android.support.v7.app.AlertDialog下的；否则在Android 5.0以下版本，依然是不透明。